WebRTC Connection Timeout and TLS Exception

[JulianSchmidt1996]

Hey,
I'm trying to set up a simple WebRTC media transfer with audio/video using SipSorcery.

I'm currently having a problem where my connection times out, and I haven't been able to figure out why.
The ICE connection between my two clients was established and is running in Connected status. The connection state runs connecting, then closed, then failed. In Visual Studio, I get these warnings:
Exception thrown: “System.Net.Sockets.SocketException” in System.Net.Sockets.dll
Exception thrown: “System.TimeoutException” in SIPSorcery.dll
Exception thrown: “Org.BouncyCastle.Tls.TlsFatalAlert” in BouncyCastle.Cryptography.dll.

Here is the source code:

using SIPSorcery.Media;
using SIPSorcery.Net;
using SIPSorceryMedia.Windows;
using System.Text.Json;
using System.Windows;
using TinyJson;
using WebSocketSharp;

namespace mySIPSorcery
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    /// 

    public partial class MainWindow : Window
    {
        private RTCPeerConnection? _peerConnection;

        private WebSocket? _webSocket;


        public MainWindow()
        {
            InitializeComponent();

        }

        public class SignalingMessage
        {
            public string? type { get; set; }

            public object? data { get; set; }
        }

        private void InitializeWebRTC(string signalingServerUrl)

        {

            // Initialize WebRTC configuration
            RTCConfiguration config = new RTCConfiguration

            {

            };



            _peerConnection = new RTCPeerConnection(config);

            // Events
            _peerConnection.onconnectionstatechange += state =>
            {
                Dispatcher.Invoke(() => lstLog.Items.Add($"Connection state: {state}"));
            };

            _peerConnection.oniceconnectionstatechange += (state) =>
            {
                Dispatcher.Invoke(() =>
                {
                    lstLog.Items.Add($"ICE Connection State changed: {state}");
                });
            };

            _peerConnection.onicecandidate += candidate =>

            {
                // Kandidaten an Gegenstelle senden via WebSocket
                if (_webSocket != null && _webSocket.ReadyState == WebSocketState.Open)
                {
                    _webSocket.Send(JsonSerializer.Serialize(new SignalingMessage
                    {
                        type = "candidate",
                        data = candidate
                    }));
                }
            };

            _peerConnection.OnTimeout += timeout =>
            {
                Dispatcher.Invoke(() => lstLog.Items.Add($"PeerConnection Timeout: {timeout.ToJson}"));
            };

            var _audioSource = new WindowsAudioEndPoint(new AudioEncoder());
            var audioFormat = _audioSource.GetAudioSourceFormats().FirstOrDefault();
            var audioTrack = new MediaStreamTrack(audioFormat, MediaStreamStatusEnum.RecvOnly);
            _peerConnection.addTrack(audioTrack);

            // Establish WebSocket connection for signaling

            _webSocket = new WebSocket(signalingServerUrl);

            if (signalingServerUrl.StartsWith("wss://"))
            {
                //TLS Konfiguration umgehen nur DEV!
                _webSocket.SslConfiguration.ServerCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;
            }

            _webSocket.OnOpen += (sender, e) =>
            {
                // Lokale Beschreibung erstellen (Offer)
                var offer = _peerConnection.createOffer(null);
                _peerConnection.setLocalDescription(offer);

                // SDP an den Signalisierungsserver schicken
                _webSocket.Send(JsonSerializer.Serialize(new SignalingMessage
                {
                    type = "offer",
                    data = offer
                }));

                Dispatcher.Invoke(() => lstLog.Items.Add("Sent offer."));


            };

            _webSocket.OnClose += (sender, e) =>
            {
                lstLog.Items.Add($"WebSocket Verbindung geschlossen. Grund: {e.Reason}, Code: {e.Code}");
            };

            _webSocket.OnError += (sender, e) =>
            {
                lstLog.Items.Add($"WebSocket Fehler: {e.Message}");
            };


            _webSocket.OnMessage += (sender, e) =>

            {

                string message = e.IsBinary ? System.Text.Encoding.UTF8.GetString(e.RawData, 0, e.RawData.Length) : e.Data;
                var msg = JsonSerializer.Deserialize<SignalingMessage>(message);

                lstLog.Items.Add($"Signaling Message: {message}");

                if (msg == null || msg.type == null || msg.data == null)
                    return;
                var data = msg.data.ToString();

                if (msg.type == "offer" && data != null)

                {
                    var offerData = JsonSerializer.Deserialize<RTCSessionDescriptionInit>(data);
                    if (offerData == null)
                        return;

                    var offer = new RTCSessionDescriptionInit

                    {

                        type = RTCSdpType.offer,

                        sdp = offerData.sdp

                    };

                    _peerConnection.setRemoteDescription(offer);

                    var answer = new RTCSessionDescriptionInit
                    {
                        type = RTCSdpType.answer,
                        sdp = _peerConnection.CreateAnswer(null).ToString()
                    };

                    _peerConnection.setLocalDescription(answer);

                    _webSocket.Send(JsonSerializer.Serialize(new SignalingMessage
                    {
                        type = "answer",
                        data = answer
                    }));

                    lstLog.Items.Add($"Msg Offer received and answer sended: {answer.toJSON()}");

                }

                else if (msg.type == "answer" && data != null)

                {
                    var answerData = JsonSerializer.Deserialize<RTCSessionDescriptionInit>(data);
                    if (answerData == null)
                        return;

                    var answer = new RTCSessionDescriptionInit

                    {

                        type = RTCSdpType.answer,

                        sdp = answerData.sdp

                    };

                    _peerConnection.setRemoteDescription(answer);

                    lstLog.Items.Add($"Msg Answer received: {answer.toJSON()}");

                }

                else if (msg.type == "candidate" && data != null)

                {                   
                    var candidateData = JsonSerializer.Deserialize<RTCIceCandidateInit>(data);
                    if (candidateData == null) return;
                    _peerConnection.addIceCandidate(candidateData);
                    lstLog.Items.Add($"Msg candidate received: {candidateData.toJSON()}");

                }

            };
            

            _webSocket.Connect();


            

        }

        private void btnConnect_Click(object sender, RoutedEventArgs e)
        {
            InitializeWebRTC("ws://localhost:8081");
        }
    }
}

I am currently testing the code exclusively on my local network without any complex firewalls in between. However, I have already checked whether simple things like disabling the Windows firewall or using a different router would help, but this was not the case. Wireshark did not provide me with any new insights in this regard, but I am happy to send you the recording.

Maybe someone else has an idea of what else I can try or what the problem might be. I look forward to your feedback.

Best regards,
Julian

[sipsorcery]

Are both your peers using sipsorcery or is one peer a browser?

If both peers are sipsorcery you could check a connection can be established on your machine using the webrtccmdline app:

Start the first peer (it's called a server due tot he signalling) using:

dotnet run --echoserver

and the second

dotnet run --echoclient http://localhost:8080/offer

Exmaple server peer output:

c:\dev\sipsorcery\examples\webrtccmdline>dotnet run --echoserver
Using launch settings from c:\dev\sipsorcery\examples\webrtccmdline\Properties\launchSettings.json...
WebRTC Console Test Program
Press ctrl-c to exit.
WebServer New State - Loading
WebServer New State - Listening
 12:24:26.742 INF >> [WebServer] Running HTTPListener: Unosquare HTTP Listener
 12:24:26.744 INF >> [WebServer] Web server prefix 'http://*:8080/' added.
 12:24:26.765 INF >> [WebServer] Started HTTP Listener
ctrl-c to exit.
[12:24:36 DBG] CreateRtpSocket attempting to create and bind RTP socket(s) on [::]:0.
[12:24:36 DBG] CreateBoundSocket attempting to create and bind socket(s) on [::]:0 using protocol Udp.
[12:24:36 DBG] CreateBoundSocket successfully bound on [::]:54086, dual mode True.
[12:24:36 DBG] Successfully bound RTP socket [::]:54086 (dual mode True).
[12:24:36 DBG] RTPChannel for [::]:54086 started.
[12:24:36 DBG] SCTP windows size for data receiver set at 218.
[12:24:36 DBG] SCTP creating DTLS based association, is DTLS client False, ID 5000:5000:54086.
[12:24:36 DBG] Setting remote audio track with sdp destination null and control destination null.
[12:24:36 DBG] RTP ICE Channel remote credentials set.
[12:24:36 INF] ICE connection state changed to checking.
[12:24:36 DBG] RTP ICE Channel received remote candidate: 2229676562 1 udp 2113937663 192.168.1.123 56160 typ host generation 0
[12:24:36 DBG] RTP ICE Channel received remote candidate: 361763198 1 udp 2113940223 fdec:d98b:83d0:4340:7cf4:84ca:769b:b976 56160 typ host generation 0
[12:24:36 DBG] RTP ICE Channel received remote candidate: 4076495844 1 udp 2113940223 fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d 56160 typ host generation 0
[12:24:36 DBG] LogRemoteSDPSsrcAttributes: Audio:[ 1066729393 - ]
 Video: [ ]
 Text: [  ]
[12:24:36 INF] Signaling state changed to have_remote_offer.
[12:24:36 DBG] RTP ICE Channel discovered 3 local candidates.
[12:24:36 DBG] Adding new candidate pair to checklist for: udp:[::]:54086 (host)->udp:192.168.1.123:56160 (host)
[12:24:36 DBG] Adding new candidate pair to checklist for: udp:[::]:54086 (host)->udp:[fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:56160 (host)
[12:24:36 DBG] Adding new candidate pair to checklist for: udp:[::]:54086 (host)->udp:[fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d]:56160 (host)
[12:24:36 DBG] ICE RTP channel sending connectivity check for udp:[::]:54086 (host)->udp:[fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:56160 (host) from [::]:54086 to [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:56160 (use candidate False).
[12:24:36 INF] Signaling state changed to stable.
[12:24:36 DBG] Setting peer connection close timeout to 10 seconds.
 12:24:36.715 INF >> [WebServer] [fLJBwxP5iEqKNvSPRvn+Mw] POST /offer: "200 OK" sent in 354ms (chunked)
[12:24:36 DBG] ICE RTP channel sending connectivity check for udp:[::]:54086 (host)->udp:[fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d]:56160 (host) from [::]:54086 to [fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d]:56160 (use candidate False).
[12:24:36 DBG] ICE RTP channel remote peer nominated entry from binding request: udp:[fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:56160 (host).
[12:24:36 DBG] ICE RTP channel connected after 161ms udp:[::]:54086 (host)->udp:[fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:56160 (host).
[12:24:36 INF] ICE connection state changed to connected.
[12:24:36 INF] Peer connection state changed to connecting.
[12:24:36 DBG] ICE connected to remote end point [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:56160.
[12:24:36 DBG] Starting DLS handshake with role active.
[12:24:36 DBG] RTCPeerConnection DoDtlsHandshake started.
[12:24:36 DBG] DTLS commencing handshake as client.
[12:24:36 DBG] RTCPeerConnection DTLS handshake result True, is handshake complete True.
[12:24:36 DBG] RTCPeerConnection remote certificate fingerprint matched expected value of 0F:E6:22:14:01:99:99:68:B7:01:2C:02:54:39:4C:AC:C7:5C:AA:9D:0F:54:1F:84:DE:9D:AD:D4:30:0D:6C:CE for sha-256.
[12:24:36 INF] Peer connection state changed to connected.
[12:24:36 DBG] Starting RTCP session for 4cb0bb5f-3d0c-4b94-a9ed-1d87f0feb0c9.
[12:24:37 DBG] SCTP INIT packet received, initial tag 3498430329, initial TSN 309161817.
[12:24:37 DBG] Set remote track (audio - index=0) SSRC to 1066729393 remote RTP endpoint [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:56160.
[12:24:37 DBG] Cookie: {"SourcePort":5000,"DestinationPort":5000,"RemoteTag":3498430329,"RemoteTSN":309161817,"RemoteARwnd":262144,"RemoteEndPoint":"","Tag":1229795295,"TSN":1219974880,"ARwnd":262144,"CreatedAt":"2025-10-18T12:24:37.0727454+01:00","Lifetime":60,"HMAC":"DA270765F979F6AA4F295ED7C3854F9892E827BD14DDCA97A0E7481F97021AA7"}
[12:24:37 DBG] SCTP transport successfully connected.
[12:24:37 DBG] SCTP association data send thread started for association 5000:5000:54086.
[12:24:37 DBG] DCEP OPEN channel type 0, priority 0, reliability 0, label dcx, protocol null.
[12:24:37 INF] WebRTC new data channel opened by remote peer for stream ID 1, type DATA_CHANNEL_RELIABLE, priority 0, reliability 0, label dcx, protocol null.
[12:24:37 INF] Data channel opened for label dcx, stream ID 1.
[12:24:40 DBG] RTCP packet received from [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:56160 81C8000C3F94FFB16670FCCFB80F1C7A8110268D5E7CAF225B4B73B32FEBB280C10BB785ED59D0D66E496C72F313394892525057FF071EB65ED38C90BB2F4833C9BDB8BB3DDEDDD18FF686ED87CA142C72A974131BFC778A413E711EC299896F0C5D96DE80000000E225F96FA6460EB5193F
[12:24:46 WRN] Test timed out.
[12:24:46 DBG] Peer connection closed with reason normal.
[12:24:46 DBG] Data channel with id 1 has been closed

Client peer output:

c:\dev\sipsorcery\examples\webrtccmdline>dotnet run --echoclient http://localhost:8080/offer
Using launch settings from c:\dev\sipsorcery\examples\webrtccmdline\Properties\launchSettings.json...
WebRTC Console Test Program
Press ctrl-c to exit.
[12:24:36 DBG] No DTLS certificate is provided in the configuration
[12:24:36 DBG] CreateRtpSocket attempting to create and bind RTP socket(s) on [::]:0.
[12:24:36 DBG] CreateBoundSocket attempting to create and bind socket(s) on [::]:0 using protocol Udp.
[12:24:36 DBG] CreateBoundSocket even port required, closing socket on [::]:56159 and retrying on 56160.
[12:24:36 DBG] Successfully bound RTP socket [::]:56160 (dual mode True).
[12:24:36 DBG] RTPChannel for [::]:56160 started.
[12:24:36 DBG] SCTP windows size for data receiver set at 218.
[12:24:36 DBG] SCTP creating DTLS based association, is DTLS client False, ID 5000:5000:56160.
[12:24:36 DBG] Data channel create request for label dcx.
[12:24:36 DBG] Waiting for ICE gaterhing to complete.
[12:24:36 DBG] onicecandidate 4076495844 1 udp 2113940223 fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d 56160 typ host generation 0
[12:24:36 DBG] onicecandidate 361763198 1 udp 2113940223 fdec:d98b:83d0:4340:7cf4:84ca:769b:b976 56160 typ host generation 0
[12:24:36 DBG] onicecandidate 2229676562 1 udp 2113937663 192.168.1.123 56160 typ host generation 0
[12:24:36 DBG] RTP ICE Channel discovered 3 local candidates.
[12:24:36 DBG] ICE gathering state changed to complete.
[12:24:36 DBG] Attempting to send offer to echo server at http://localhost:8080/offer.
[12:24:36 DBG] Local SDP:
[12:24:36 DBG] v=0
o=- 40904 0 IN IP4 127.0.0.1
s=sipsorcery
t=0 0
a=group:BUNDLE 0 1
m=audio 9 UDP/TLS/RTP/SAVP 0 8 9 18 101
c=IN IP4 0.0.0.0
a=ice-ufrag:PNNB
a=ice-pwd:OWCRRSSOWEPIRBZIAFPVNKIF
a=fingerprint:sha-256 0F:E6:22:14:01:99:99:68:B7:01:2C:02:54:39:4C:AC:C7:5C:AA:9D:0F:54:1F:84:DE:9D:AD:D4:30:0D:6C:CE
a=setup:actpass
a=candidate:2229676562 1 udp 2113937663 192.168.1.123 56160 typ host generation 0
a=candidate:361763198 1 udp 2113940223 fdec:d98b:83d0:4340:7cf4:84ca:769b:b976 56160 typ host generation 0
a=candidate:4076495844 1 udp 2113940223 fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d 56160 typ host generation 0
a=mid:0
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:9 G722/8000
a=rtpmap:18 G729/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ice-options:ice2,trickle
a=rtcp-mux
a=rtcp:9 IN IP4 0.0.0.0
a=sendonly
a=ssrc:1066729393 cname:cfecb1ce-3a26-4c42-9af5-8be9641dce60
m=application 9 UDP/DTLS/SCTP webrtc-datachannel
c=IN IP4 0.0.0.0
a=ice-ufrag:PNNB
a=ice-pwd:OWCRRSSOWEPIRBZIAFPVNKIF
a=fingerprint:sha-256 0F:E6:22:14:01:99:99:68:B7:01:2C:02:54:39:4C:AC:C7:5C:AA:9D:0F:54:1F:84:DE:9D:AD:D4:30:0D:6C:CE
a=setup:actpass
a=mid:1
a=ice-options:ice2,trickle
a=sctp-port:5000
a=max-message-size:262144

[12:24:36 DBG] Adding peer reflex ICE candidate for [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086.
[12:24:36 DBG] Adding new candidate pair to checklist for: udp:[::]:56160 (host)->udp:[fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086 (prflx)
[12:24:36 DBG] Setting remote audio track with sdp destination null and control destination null.
[12:24:36 DBG] RTP ICE Channel remote credentials set.
[12:24:36 DBG] ICE connection state change to checking.
[12:24:36 DBG] RTP ICE Channel received remote candidate: 2229676562 1 udp 2113937663 192.168.1.123 54086 typ host generation 0
[12:24:36 DBG] RTP ICE Channel received remote candidate: 361763198 1 udp 2113940223 fdec:d98b:83d0:4340:7cf4:84ca:769b:b976 54086 typ host generation 0
[12:24:36 DBG] RTP ICE Channel received remote candidate: 4076495844 1 udp 2113940223 fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d 54086 typ host generation 0
[12:24:36 DBG] LogRemoteSDPSsrcAttributes: Audio:[ 1732710600 - ]
 Video: [ ]
 Text: [  ]
[12:24:36 DBG] Adding peer reflex ICE candidate for [fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d]:54086.
[12:24:36 DBG] Remote SDP:
[12:24:36 DBG] Adding new candidate pair to checklist for: udp:[::]:56160 (host)->udp:[fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d]:54086 (prflx)
[12:24:36 DBG] v=0
o=- 88212 0 IN IP4 127.0.0.1
s=sipsorcery
t=0 0
a=group:BUNDLE 0 1
m=audio 9 UDP/TLS/RTP/SAVP 0 101
c=IN IP4 0.0.0.0
a=ice-ufrag:WFVN
a=ice-pwd:COHWBXTVQPHNBMOTZDRLWXNM
a=fingerprint:sha-256 FC:D8:B1:B9:D7:13:AA:F5:F7:B7:7B:6E:4F:1F:44:4C:86:94:74:A6:69:9D:7E:28:92:6E:78:6C:C5:57:E6:BF
a=setup:active
a=candidate:2229676562 1 udp 2113937663 192.168.1.123 54086 typ host generation 0
a=candidate:361763198 1 udp 2113940223 fdec:d98b:83d0:4340:7cf4:84ca:769b:b976 54086 typ host generation 0
a=candidate:4076495844 1 udp 2113940223 fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d 54086 typ host generation 0
a=mid:0
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ice-options:ice2,trickle
a=rtcp-mux
a=rtcp:9 IN IP4 0.0.0.0
a=sendrecv
a=ssrc:1732710600 cname:4cb0bb5f-3d0c-4b94-a9ed-1d87f0feb0c9
m=application 9 UDP/DTLS/SCTP webrtc-datachannel
c=IN IP4 0.0.0.0
a=ice-ufrag:WFVN
a=ice-pwd:COHWBXTVQPHNBMOTZDRLWXNM
a=fingerprint:sha-256 FC:D8:B1:B9:D7:13:AA:F5:F7:B7:7B:6E:4F:1F:44:4C:86:94:74:A6:69:9D:7E:28:92:6E:78:6C:C5:57:E6:BF
a=setup:active
a=mid:1
a=ice-options:ice2,trickle
a=sctp-port:5000
a=max-message-size:262144

[12:24:36 DBG] Adding new candidate pair to checklist for: udp:[::]:56160 (host)->udp:192.168.1.123:54086 (host)
[12:24:36 DBG] Removing lower priority entry and adding candidate pair to checklist for: 361763198 1 udp 2113940223 fdec:d98b:83d0:4340:7cf4:84ca:769b:b976 54086 typ host generation 0
[12:24:36 DBG] Removing lower priority entry and adding candidate pair to checklist for: 4076495844 1 udp 2113940223 fdec:d98b:83d0:4340:6d84:bf2d:8ee9:654d 54086 typ host generation 0
[12:24:36 DBG] ICE RTP channel sending connectivity check for udp:[::]:56160 (host)->udp:[fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086 (host) from [::]:56160 to [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086 (use candidate False).
[12:24:36 DBG] ICE RTP channel binding response state Succeeded as Controller for udp:[fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086 (host)
[12:24:36 DBG] ICE RTP channel sending connectivity check for udp:[::]:56160 (host)->udp:[fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086 (host) from [::]:56160 to [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086 (use candidate True).
[12:24:36 DBG] ICE RTP channel remote peer nominated entry from binding response udp:[fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086 (host)
[12:24:36 DBG] ICE RTP channel connected after 546ms udp:[::]:56160 (host)->udp:[fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086 (host).
[12:24:36 DBG] ICE connection state change to connected.
[12:24:36 DBG] Peer connection state changed to connecting.
[12:24:36 DBG] ICE connected to remote end point [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086.
[12:24:36 DBG] Starting DLS handshake with role passive.
[12:24:36 DBG] RTCPeerConnection DoDtlsHandshake started.
[12:24:36 DBG] DTLS commencing handshake as server.
[12:24:36 VRB] Server offered cipher suites:
 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
 DRAFT_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
[12:24:36 VRB] Client offered cipher suites:
 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
 DRAFT_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
 TLS_EMPTY_RENEGOTIATION_INFO_SCSV
[12:24:36 DBG] RTCPeerConnection DTLS handshake result True, is handshake complete True.
[12:24:36 DBG] RTCPeerConnection remote certificate fingerprint matched expected value of FC:D8:B1:B9:D7:13:AA:F5:F7:B7:7B:6E:4F:1F:44:4C:86:94:74:A6:69:9D:7E:28:92:6E:78:6C:C5:57:E6:BF for sha-256.
[12:24:36 DBG] Peer connection state changed to connected.
[12:24:36 DBG] Starting RTCP session for cfecb1ce-3a26-4c42-9af5-8be9641dce60.
[12:24:37 VRB] SCTP state for association 5000:5000:56160 changed to CookieWait.
[12:24:37 DBG] Set remote track (audio - index=0) SSRC to 1732710600 remote RTP endpoint [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086.
[12:24:37 VRB] SCTP state for association 5000:5000:56160 changed to CookieEchoed.
[12:24:37 VRB] SCTP state for association 5000:5000:56160 changed to Established.
[12:24:37 DBG] SCTP transport successfully connected.
[12:24:37 DBG] WebRTC attempting to open data channel with label dcx and stream ID 1.
[12:24:37 DBG] SCTP transport for create data channel request changed to state Connected.
[12:24:37 DBG] SCTP association data send thread started for association 5000:5000:56160.
[12:24:37 VRB] SCTP resending missing data chunk for TSN 309161817, data length 15, flags 03, send count 1.
[12:24:37 VRB] SCTP first SACK remote peer TSN ACK 309161817 next sender TSN 309161818, arwnd 262144 (gap reports 0).
[12:24:37 VRB] SCTP data sender removing unconfirmed chunks cumulative ACK TSN 309161817, SACK TSN 309161817.
[12:24:37 VRB] SCTP data chunk received on ID 5000:5000:56160 with TSN 1219974880, payload length 1, flags 3.
[12:24:37 VRB] SCTP receiver got data chunk with TSN 1219974880, last in order TSN 0, in order receive count 0.
[12:24:37 DBG] WebRTC data channel opened label dcx and stream ID 1.
[12:24:37 DBG] Data channel for label dcx now open.
[12:24:44 DBG] RTCP packet received from [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086 81C8000C674710C8A810A2D068BB7B2DD3ED39260A478B37C48854D84A5A7C47AFF5DEC863B334AAF41E678D33E6415269F91494D0E22B6EDCA3767DEACC4C31F4BC1F60443DB139A0AD67033B164C4EA9B0DA23519A01E8A4100D8AD7E627FBF5C70043800000008FAE72A647FEEF2CF9C5
[12:24:46 DBG] DTLS server received close notification: warning(1), close_notify(0).
[12:24:46 DBG] SCTP closing transport as a result of DTLS close notification.
[12:24:46 DBG] RTCP packet received from [fdec:d98b:83d0:4340:7cf4:84ca:769b:b976]:54086 81C8000C674710C8FE03A2F1E1CE50327B306C0799422CD3D86FAA6EE915DC41067D148766B83BD46373887997ADB4147ED21E408C1DD60AD6EAD0FA999031F28E4566D9733AE62FB1A497C1DC145D0D4C32A72363ABA365F662465D9F14EDA8ED57F7DEDD8A3CD29235B0E2E42BE012C49F380E80000001C5CE67B08B7A7D7314D4
[12:24:46 VRB] SCTP state for association 5000:5000:56160 changed to ShutdownPending.
[12:24:46 DBG] RTCP BYE received for SSRC 1732710600, reason normal.
[12:24:46 VRB] SCTP sending shutdown for association 5000:5000:56160, ACK TSN 1219974880.
[12:24:46 DBG] RTCP session removing reception report for remote ssrc 1732710600.
[12:24:46 VRB] SCTP state for association 5000:5000:56160 changed to ShutdownSent.
[12:24:46 DBG] DTLS server raised close notify: warning(1), close_notify(0).
[12:24:46 DBG] DTLS server raised close notify: warning(1), close_notify(0).
[12:24:47 DBG] SCTP transport for create data channel request changed to state Closed.
[12:24:49 DBG] SCTP association data send thread stopped for association 5000:5000:56160.

Exiting...
[12:24:52 DBG] Peer connection closed with reason application exit.
[12:24:52 DBG] Data channel with id 1 has been closed
[12:24:52 DBG] RtpIceChannel for [::]:56160 closed.
[12:24:52 WRN] SendRtpRaw was called for a audio packet on a closed RTP session.
[12:24:52 DBG] RTPChannel closing, RTP receiver on port 56160. Reason: application exit.
[12:24:52 DBG] Peer connection state changed to closed.

[JulianSchmidt1996]

Hello Aaron,

Thanks for the quick reply.

To answer your first question, both clients are sipsorcery.

I ran the WebRCTCMD-Line app, and the handshake and connection establishment seem to work here.

server peer output:

PS` Z:\Benutzer Daten\Desktop\sipsorcery\sipsorcery\sipsorcery\examples\webrtccmdline> dotnet run --echoserver
Die Starteinstellungen von Z:\Benutzer Daten\Desktop\sipsorcery\sipsorcery\sipsorcery\examples\webrtccmdline\Properties\launchSettings.json werden verwendet…
WebRTC Console Test Program
Press ctrl-c to exit.
 09:19:42.711 INF >> [WebServer] Running HTTPListener: Unosquare HTTP Listener
 09:19:42.724 INF >> [WebServer] Web server prefix 'http://*:8080/' added.
WebServer New State - Loading
WebServer New State - Listening
ctrl-c to exit.
 09:19:42.789 INF >> [WebServer] Started HTTP Listener
[09:21:17 DBG] CreateRtpSocket attempting to create and bind RTP socket(s) on [::]:0.
[09:21:17 DBG] CreateBoundSocket attempting to create and bind socket(s) on [::]:0 using protocol Udp.
[09:21:17 DBG] CreateBoundSocket even port required, closing socket on [::]:52017 and retrying on 52018.
[09:21:17 DBG] Successfully bound RTP socket [::]:52018 (dual mode True).
[09:21:17 DBG] RTPChannel for [::]:52018 started.
[09:21:17 DBG] SCTP windows size for data receiver set at 218.
[09:21:17 DBG] SCTP creating DTLS based association, is DTLS client False, ID 5000:5000:52018.
[09:21:17 DBG] Setting remote audio track with destination null and control destination null.
[09:21:17 DBG] RTP ICE Channel discovered 3 local candidates.
[09:21:17 DBG] RTP ICE Channel remote credentials set.
[09:21:17 INF] ICE connection state changed to checking.
[09:21:17 DBG] RTP ICE Channel received remote candidate: 3634590365 1 udp 2113937663 192.168.2.124 51946 typ host generation 0
[09:21:17 DBG] RTP ICE Channel received remote candidate: 2105281575 1 udp 2113940223 fd91:dab6:a2b2:1:69e9:f98e:1527:4a97 51946 typ host generation 0
[09:21:17 DBG] Adding new candidate pair to checklist for: udp:[::]:52018 (host)->udp:192.168.2.124:51946 (host)
[09:21:17 DBG] RTP ICE Channel received remote candidate: 584056500 1 udp 2113940223 fd91:dab6:a2b2:1:8578:da86:c2fd:81ce 51946 typ host generation 0
[09:21:17 DBG] Adding new candidate pair to checklist for: udp:[::]:52018 (host)->udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:51946 (host)
[09:21:17 DBG] LogRemoteSDPSsrcAttributes: Audio:[ 1145671410 - ]
 Video: [ ]
 Text: [  ]
[09:21:17 DBG] Adding new candidate pair to checklist for: udp:[::]:52018 (host)->udp:[fd91:dab6:a2b2:1:8578:da86:c2fd:81ce]:51946 (host)
[09:21:17 INF] Signaling state changed to have_remote_offer.
[09:21:17 DBG] ICE RTP channel sending connectivity check for udp:[::]:52018 (host)->udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:51946 (host) from [::]:52018 to [fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:51946 (use candidate False).
[09:21:17 INF] Signaling state changed to stable.
[09:21:17 DBG] ICE RTP channel sending connectivity check for udp:[::]:52018 (host)->udp:[fd91:dab6:a2b2:1:8578:da86:c2fd:81ce]:51946 (host) from [::]:52018 to [fd91:dab6:a2b2:1:8578:da86:c2fd:81ce]:51946 (use candidate False).
[09:21:17 DBG] ICE RTP channel sending connectivity check for udp:[::]:52018 (host)->udp:192.168.2.124:51946 (host) from [::]:52018 to 192.168.2.124:51946 (use candidate False).
[09:21:18 DBG] Setting peer connection close timeout to 10 seconds.
 09:21:18.083 INF >> [WebServer] [sm2CfPHHt0aOTV8zGqoAYA] POST /offer: "200 OK" sent in 1455ms (chunked)
[09:21:18 DBG] ICE RTP channel remote peer nominated entry from binding request: udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:51946 (host).
[09:21:18 DBG] ICE RTP channel connected after 827ms udp:[::]:52018 (host)->udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:51946 (host).
[09:21:18 INF] ICE connection state changed to connected.
[09:21:18 INF] Peer connection state changed to connecting.
[09:21:18 DBG] ICE connected to remote end point [fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:51946.
[09:21:18 DBG] Starting DLS handshake with role active.
[09:21:18 DBG] RTCPeerConnection DoDtlsHandshake started.
[09:21:18 DBG] DTLS commencing handshake as client.
[09:21:18 DBG] RTCPeerConnection DTLS handshake result True, is handshake complete True.
[09:21:19 DBG] RTCPeerConnection remote certificate fingerprint matched expected value of FB:7B:3F:4D:54:31:B7:9C:5A:98:B6:C2:25:E7:6D:3C:28:90:30:09:CA:99:9E:4E:29:4F:CE:F0:99:C9:B3:35 for sha-256.
[09:21:19 WRN] RTP or RTCP packet received before secure context ready.
[09:21:19 INF] Peer connection state changed to connected.
[09:21:19 DBG] Set remote track (audio - index=0) SSRC to 1145671410 remote RTP endpoint [fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:51946.
[09:21:19 DBG] Starting RTCP session for d52f04e9-2b5d-4736-9290-74056048d728.
[09:21:19 DBG] SCTP INIT packet received, initial tag 3319233108, initial TSN 2291287997.
[09:21:19 DBG] Cookie: {"SourcePort":5000,"DestinationPort":5000,"RemoteTag":3319233108,"RemoteTSN":2291287997,"RemoteARwnd":262144,"RemoteEndPoint":"","Tag":1301902482,"TSN":3597025943,"ARwnd":262144,"CreatedAt":"2025-10-22T09:21:19.7033943+02:00","Lifetime":60,"HMAC":"68FA944F36193226AFE31F69D9CAD847171296A483E7FE53625BEDD8A24713B4"}
[09:21:19 DBG] SCTP transport successfully connected.
[09:21:19 DBG] SCTP association data send thread started for association 5000:5000:52018.
[09:21:20 DBG] DCEP OPEN channel type 0, priority 0, reliability 0, label dcx, protocol null.
[09:21:20 INF] WebRTC new data channel opened by remote peer for stream ID 1, type DATA_CHANNEL_RELIABLE, priority 0, reliability 0, label dcx, protocol null.
[09:21:20 INF] Data channel opened for label dcx, stream ID 1.
[09:21:28 WRN] Test timed out.
[09:21:28 DBG] Peer connection closed with reason normal.
[09:21:28 DBG] Data channel with id 1 has been closed
[09:21:28 DBG] RtpIceChannel for [::]:52018 closed.
[09:21:28 DBG] DTLS client raised close notification: warning(1), close_notify(0).
[09:21:28 DBG] RTPChannel closing, RTP receiver on port 52018. Reason: normal.
[09:21:28 INF] Peer connection state changed to closed.
[09:21:29 DBG] SCTP association data send thread stopped for association 5000:5000:52018.

Client peer Output

PS Z:\Benutzer Daten\Desktop\sipsorcery\sipsorcery\sipsorcery\examples\webrtccmdline> dotnet run --echoclient http://localhost:8080/offer
Die Starteinstellungen von Z:\Benutzer Daten\Desktop\sipsorcery\sipsorcery\sipsorcery\examples\webrtccmdline\Properties\launchSettings.json werden verwendet…
WebRTC Console Test Program
Press ctrl-c to exit.
[09:21:15 DBG] No DTLS certificate is provided in the configuration
[09:21:16 DBG] CreateRtpSocket attempting to create and bind RTP socket(s) on [::]:0.
[09:21:16 DBG] CreateBoundSocket attempting to create and bind socket(s) on [::]:0 using protocol Udp.
[09:21:16 DBG] CreateBoundSocket even port required, closing socket on [::]:51945 and retrying on 51946.
[09:21:16 DBG] Successfully bound RTP socket [::]:51946 (dual mode True).
[09:21:16 DBG] RTPChannel for [::]:51946 started.
[09:21:16 DBG] SCTP windows size for data receiver set at 218.
[09:21:16 DBG] SCTP creating DTLS based association, is DTLS client False, ID 5000:5000:51946.
[09:21:16 DBG] Data channel create request for label dcx.
[09:21:16 DBG] Waiting for ICE gaterhing to complete.
[09:21:16 DBG] onicecandidate 584056500 1 udp 2113940223 fd91:dab6:a2b2:1:8578:da86:c2fd:81ce 51946 typ host generation 0
[09:21:16 DBG] onicecandidate 2105281575 1 udp 2113940223 fd91:dab6:a2b2:1:69e9:f98e:1527:4a97 51946 typ host generation 0
[09:21:16 DBG] onicecandidate 3634590365 1 udp 2113937663 192.168.2.124 51946 typ host generation 0
[09:21:16 DBG] RTP ICE Channel discovered 3 local candidates.
[09:21:16 DBG] ICE gathering state changed to complete.
[09:21:16 DBG] Attempting to send offer to echo server at http://localhost:8080/offer.
[09:21:16 DBG] Local SDP:
[09:21:16 DBG] v=0
o=- 84909 0 IN IP4 127.0.0.1
s=sipsorcery
t=0 0
a=group:BUNDLE 0 1
m=audio 9 UDP/TLS/RTP/SAVP 0 8 9 18 101
c=IN IP4 0.0.0.0
a=ice-ufrag:UDXK
a=ice-pwd:PNFZHEIEZFZUNFUAVHOHKYUZ
a=fingerprint:sha-256 FB:7B:3F:4D:54:31:B7:9C:5A:98:B6:C2:25:E7:6D:3C:28:90:30:09:CA:99:9E:4E:29:4F:CE:F0:99:C9:B3:35
a=setup:actpass
a=candidate:3634590365 1 udp 2113937663 192.168.2.124 51946 typ host generation 0
a=candidate:2105281575 1 udp 2113940223 fd91:dab6:a2b2:1:69e9:f98e:1527:4a97 51946 typ host generation 0
a=candidate:584056500 1 udp 2113940223 fd91:dab6:a2b2:1:8578:da86:c2fd:81ce 51946 typ host generation 0
a=mid:0
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:9 G722/8000
a=rtpmap:18 G729/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ice-options:ice2,trickle
a=rtcp-mux
a=rtcp:9 IN IP4 0.0.0.0
a=sendonly
a=ssrc:1145671410 cname:0030037c-2ff0-4363-9abc-235bc014afa6
m=application 9 UDP/DTLS/SCTP webrtc-datachannel
c=IN IP4 0.0.0.0
a=ice-ufrag:UDXK
a=ice-pwd:PNFZHEIEZFZUNFUAVHOHKYUZ
a=fingerprint:sha-256 FB:7B:3F:4D:54:31:B7:9C:5A:98:B6:C2:25:E7:6D:3C:28:90:30:09:CA:99:9E:4E:29:4F:CE:F0:99:C9:B3:35
a=setup:actpass
a=mid:1
a=ice-options:ice2,trickle
a=sctp-port:5000
a=max-message-size:262144

[09:21:17 DBG] Adding peer reflex ICE candidate for [fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018.
[09:21:17 DBG] Adding new candidate pair to checklist for: udp:[::]:51946 (host)->udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018 (prflx)
[09:21:18 DBG] Setting remote audio track with destination null and control destination null.
[09:21:18 DBG] Adding peer reflex ICE candidate for [fd91:dab6:a2b2:1:8578:da86:c2fd:81ce]:52018.
[09:21:18 DBG] Adding new candidate pair to checklist for: udp:[::]:51946 (host)->udp:[fd91:dab6:a2b2:1:8578:da86:c2fd:81ce]:52018 (prflx)
[09:21:18 DBG] RTP ICE Channel remote credentials set.
[09:21:18 DBG] Adding peer reflex ICE candidate for 192.168.2.124:52018.
[09:21:18 DBG] ICE connection state change to checking.
[09:21:18 DBG] Adding new candidate pair to checklist for: udp:[::]:51946 (host)->udp:192.168.2.124:52018 (prflx)
[09:21:18 DBG] RTP ICE Channel received remote candidate: 3634590365 1 udp 2113937663 192.168.2.124 52018 typ host generation 0
[09:21:18 DBG] RTP ICE Channel received remote candidate: 2105281575 1 udp 2113940223 fd91:dab6:a2b2:1:69e9:f98e:1527:4a97 52018 typ host generation 0
[09:21:18 DBG] RTP ICE Channel received remote candidate: 584056500 1 udp 2113940223 fd91:dab6:a2b2:1:8578:da86:c2fd:81ce 52018 typ host generation 0
[09:21:18 DBG] Removing lower priority entry and adding candidate pair to checklist for: 3634590365 1 udp 2113937663 192.168.2.124 52018 typ host generation 0
[09:21:18 DBG] LogRemoteSDPSsrcAttributes: Audio:[ 1285396692 - ]
 Video: [ ]
 Text: [  ]
[09:21:18 DBG] Remote SDP:
[09:21:18 DBG] Removing lower priority entry and adding candidate pair to checklist for: 2105281575 1 udp 2113940223 fd91:dab6:a2b2:1:69e9:f98e:1527:4a97 52018 typ host generation 0
[09:21:18 DBG] v=0
o=- 22394 0 IN IP4 127.0.0.1
s=sipsorcery
t=0 0
a=group:BUNDLE 0 1
m=audio 9 UDP/TLS/RTP/SAVP 0 101
c=IN IP4 0.0.0.0
a=ice-ufrag:NQWD
a=ice-pwd:SLYSHBIAWMIYSUJQURFAPMXF
a=fingerprint:sha-256 3B:8E:DF:87:29:5F:38:8B:9F:5E:05:93:07:23:C7:8F:37:18:C7:66:FA:2E:DC:F9:BE:A8:31:98:03:7F:E3:7C
a=setup:active
a=candidate:3634590365 1 udp 2113937663 192.168.2.124 52018 typ host generation 0
a=candidate:2105281575 1 udp 2113940223 fd91:dab6:a2b2:1:69e9:f98e:1527:4a97 52018 typ host generation 0
a=candidate:584056500 1 udp 2113940223 fd91:dab6:a2b2:1:8578:da86:c2fd:81ce 52018 typ host generation 0
a=mid:0
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ice-options:ice2,trickle
a=rtcp-mux
a=rtcp:9 IN IP4 0.0.0.0
a=sendrecv
a=ssrc:1285396692 cname:d52f04e9-2b5d-4736-9290-74056048d728
m=application 9 UDP/DTLS/SCTP webrtc-datachannel
c=IN IP4 0.0.0.0
a=ice-ufrag:NQWD
a=ice-pwd:SLYSHBIAWMIYSUJQURFAPMXF
a=fingerprint:sha-256 3B:8E:DF:87:29:5F:38:8B:9F:5E:05:93:07:23:C7:8F:37:18:C7:66:FA:2E:DC:F9:BE:A8:31:98:03:7F:E3:7C
a=setup:active
a=mid:1
a=ice-options:ice2,trickle
a=sctp-port:5000
a=max-message-size:262144

[09:21:18 DBG] Removing lower priority entry and adding candidate pair to checklist for: 584056500 1 udp 2113940223 fd91:dab6:a2b2:1:8578:da86:c2fd:81ce 52018 typ host generation 0
[09:21:18 DBG] ICE RTP channel sending connectivity check for udp:[::]:51946 (host)->udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018 (host) from [::]:51946 to [fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018 (use candidate False).
[09:21:18 DBG] ICE RTP channel sending connectivity check for udp:[::]:51946 (host)->udp:[fd91:dab6:a2b2:1:8578:da86:c2fd:81ce]:52018 (host) from [::]:51946 to [fd91:dab6:a2b2:1:8578:da86:c2fd:81ce]:52018 (use candidate False).
[09:21:18 DBG] ICE RTP channel binding response state Succeeded as Controller for udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018 (host)
[09:21:18 DBG] ICE RTP channel sending connectivity check for udp:[::]:51946 (host)->udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018 (host) from [::]:51946 to [fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018 (use candidate True).
[09:21:18 DBG] ICE RTP channel binding response state Succeeded as Controller for udp:[fd91:dab6:a2b2:1:8578:da86:c2fd:81ce]:52018 (host)
[09:21:18 DBG] ICE RTP channel sending connectivity check for udp:[::]:51946 (host)->udp:192.168.2.124:52018 (host) from [::]:51946 to 192.168.2.124:52018 (use candidate False).
[09:21:18 DBG] ICE RTP channel remote peer nominated entry from binding response udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018 (host)
[09:21:18 DBG] ICE RTP channel connected after 2092ms udp:[::]:51946 (host)->udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018 (host).
[09:21:18 DBG] ICE connection state change to connected.
[09:21:18 DBG] Peer connection state changed to connecting.
[09:21:18 DBG] ICE connected to remote end point [fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018.
[09:21:18 DBG] Starting DLS handshake with role passive.
[09:21:18 DBG] RTCPeerConnection DoDtlsHandshake started.
[09:21:18 DBG] DTLS commencing handshake as server.
[09:21:18 VRB] Server offered cipher suites:
 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
 DRAFT_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
[09:21:18 VRB] Client offered cipher suites:
 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
 DRAFT_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
 TLS_EMPTY_RENEGOTIATION_INFO_SCSV
[09:21:18 DBG] RTCPeerConnection DTLS handshake result True, is handshake complete True.
[09:21:18 DBG] RTCPeerConnection remote certificate fingerprint matched expected value of 3B:8E:DF:87:29:5F:38:8B:9F:5E:05:93:07:23:C7:8F:37:18:C7:66:FA:2E:DC:F9:BE:A8:31:98:03:7F:E3:7C for sha-256.
[09:21:18 DBG] Peer connection state changed to connected.
[09:21:18 DBG] Starting RTCP session for 0030037c-2ff0-4363-9abc-235bc014afa6.
[09:21:19 VRB] SCTP state for association 5000:5000:51946 changed to CookieWait.
[09:21:19 DBG] Set remote track (audio - index=0) SSRC to 1285396692 remote RTP endpoint [fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018.
[09:21:19 VRB] SCTP state for association 5000:5000:51946 changed to CookieEchoed.
[09:21:19 VRB] SCTP state for association 5000:5000:51946 changed to Established.
[09:21:19 DBG] SCTP transport successfully connected.
[09:21:19 DBG] WebRTC attempting to open data channel with label dcx and stream ID 1.
[09:21:19 DBG] SCTP transport for create data channel request changed to state Connected.
[09:21:19 DBG] SCTP association data send thread started for association 5000:5000:51946.
[09:21:20 VRB] SCTP resending missing data chunk for TSN 2291287997, data length 15, flags 03, send count 1.
[09:21:20 VRB] SCTP first SACK remote peer TSN ACK 2291287997 next sender TSN 2291287998, arwnd 262144 (gap reports 0).
[09:21:20 VRB] SCTP data sender removing unconfirmed chunks cumulative ACK TSN 2291287997, SACK TSN 2291287997.
[09:21:20 VRB] SCTP data chunk received on ID 5000:5000:51946 with TSN 3597025943, payload length 1, flags 3.
[09:21:20 VRB] SCTP receiver got data chunk with TSN 3597025943, last in order TSN 0, in order receive count 0.
[09:21:20 DBG] WebRTC data channel opened label dcx and stream ID 1.
[09:21:20 DBG] Data channel for label dcx now open.
[09:21:28 DBG] DTLS server received close notification: warning(1), close_notify(0).
[09:21:28 DBG] SCTP closing transport as a result of DTLS close notification.
[09:21:28 DBG] RTCP BYE received for SSRC 1285396692, reason normal.
[09:21:28 VRB] SCTP state for association 5000:5000:51946 changed to ShutdownPending.
[09:21:28 DBG] RTCP session removing reception report for remote ssrc 1285396692.
[09:21:28 VRB] SCTP sending shutdown for association 5000:5000:51946, ACK TSN 3597025943.
[09:21:28 VRB] SCTP state for association 5000:5000:51946 changed to ShutdownSent.
[09:21:28 DBG] DTLS server raised close notify: warning(1), close_notify(0).
[09:21:28 DBG] DTLS server raised close notify: warning(1), close_notify(0).
[09:21:28 DBG] SCTP transport for create data channel request changed to state Closed.
[09:21:29 DBG] SCTP association data send thread stopped for association 5000:5000:51946.
[09:21:36 WRN] ICE RTP channel disconnected after 9s udp:[::]:51946 (host)->udp:[fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018 (host).
[09:21:36 DBG] ICE connection state change to disconnected.
[09:21:36 DBG] Peer connection state changed to disconnected.
[09:21:36 DBG] Peer connection closed with reason remote disconnection.
[09:21:36 DBG] Data channel with id 1 has been closed
[09:21:36 DBG] RtpIceChannel for [::]:51946 closed.
[09:21:36 DBG] RTPChannel closing, RTP receiver on port 51946. Reason: remote disconnection.
[09:21:36 DBG] Peer connection state changed to closed.
[09:21:36 WRN] Error sending STUN server binding request to [fd91:dab6:a2b2:1:69e9:f98e:1527:4a97]:52018. Disconnecting.

Do you have any idea why it doesn't work with my code?