`dotnet build` results in "Unable to load the service index for source" and "Socket is not connected"

[mrlife]

Describe the bug

Running dotnet build results in the following error messages:

MSBuild version 17.9.8+b34f75857 for .NET
Determining projects to restore...
/usr/local/share/dotnet/sdk/8.0.204/NuGet.targets(169,5): error : Unable to load the service index for source https://api.nuget.org/v3/index.json. [/Users/user_name/Documents/app_name/AppName.sln]
/usr/local/share/dotnet/sdk/8.0.204/NuGet.targets(169,5): error : Socket is not connected [/Users/user_name/Documents/app_name/AppName.sln]

I'm able to view https://api.nuget.org/v3/index.json in the browser without any issues.

To Reproduce

Run dotnet build in project folder in terminal on macOS

Exceptions (if any)

Unable to load the service index for source https://api.nuget.org/v3/index.json

Socket is not connected

Further technical details

• Include the output of dotnet --info

.NET SDK:
Version: 8.0.204
Commit: c338c7548c
Workload version: 8.0.200-manifests.9f663350

Runtime Environment:
OS Name: Mac OS X
OS Version: 14.6
OS Platform: Darwin
RID: osx-arm64
Base Path: /usr/local/share/dotnet/sdk/8.0.204/

.NET workloads installed:
There are no installed workloads to display.

Host:
Version: 8.0.4
Architecture: arm64
Commit: 2d7eea2529

.NET SDKs installed:
7.0.100 [/usr/local/share/dotnet/sdk]
7.0.101 [/usr/local/share/dotnet/sdk]
7.0.200 [/usr/local/share/dotnet/sdk]
7.0.202 [/usr/local/share/dotnet/sdk]
7.0.203 [/usr/local/share/dotnet/sdk]
7.0.302 [/usr/local/share/dotnet/sdk]
7.0.304 [/usr/local/share/dotnet/sdk]
7.0.308 [/usr/local/share/dotnet/sdk]
7.0.309 [/usr/local/share/dotnet/sdk]
7.0.311 [/usr/local/share/dotnet/sdk]
7.0.312 [/usr/local/share/dotnet/sdk]
7.0.313 [/usr/local/share/dotnet/sdk]
7.0.314 [/usr/local/share/dotnet/sdk]
7.0.315 [/usr/local/share/dotnet/sdk]
7.0.316 [/usr/local/share/dotnet/sdk]
7.0.317 [/usr/local/share/dotnet/sdk]
8.0.100-rc.1.23463.5 [/usr/local/share/dotnet/sdk]
8.0.100-rc.2.23502.2 [/usr/local/share/dotnet/sdk]
8.0.100 [/usr/local/share/dotnet/sdk]
8.0.203 [/usr/local/share/dotnet/sdk]
8.0.204 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 7.0.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.1 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.3 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.7 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.11 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.12 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.14 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.15 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.16 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.17 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.18 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.19 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.20 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.0-rc.1.23421.29 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.0-rc.2.23480.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.3 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 7.0.1 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.3 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.4 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.7 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.11 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.12 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.14 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.15 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.16 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.17 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.18 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.19 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.20 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.0-rc.1.23419.4 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.0-rc.2.23479.6 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.3 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.4 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
x64 [/usr/local/share/dotnet/x64]

Environment variables:
Not set

global.json file:
Not found

[baronfel]

The 8.0.200 series of SDKs is out of support - please update your SDK to the 300 or 400 series and try again.

[mrlife]

@baronfel, thanks for the suggestion. I updated to this SDK version:

Version: 8.0.402
Commit: 70aa751718
Workload version: 8.0.400-manifests.b6724b7a
MSBuild version: 17.11.4+37eb419ad

It behaves a little differently in that it now tries 6 times, printing the following each time:

/Users/user_name/Documents/app_name/AppName.csproj : error NU1301: Unable to load the service index for source https://api.nuget.org/v3/index.json. [/Users/user_name/Documents/app_name/AppName.sln]

[mrlife]

@baronfel, the same is true for running dotnet restore. Any other ideas on the cause for the error or a solution/workaround to get past it?

[baronfel]

@nkolev92 is there any kind of first-response FAQ or troubleshooting step for networking issues during restore?

[nkolev92]

I could only find something on auth: https://github.com/NuGet/Home/wiki/Azure-DevOps-Artifacts-authentication-issues.

Generally, when we encounter issues like the guidance is try a quick console app and see if it behaves the same as dotnet restore.

cc @zivkan in case he has some generic write-ups

[zivkan]

@mrlife you can try running dotnet add package DoesNotExist, and it should give you the inner exception to the "unable to load the service index" exception. That'll tell you what the underlying cause was (we really need to fix this). edit: looks like we are reporting the inner exceptions in restore with the .NET 9 SDK

However, in the case of "socket is not connected", I've never seen that before, and don't have any ideas.

Something I sometimes ask people to do is to use dotnet new console to create a new console app, then change Program.cs to await (new HttpClient()).GetAsync("https://api.nuget.org/v3/index.json"); to verify that the same exception occurs. Change the URL to your package source if you're having this problem with a source other than nuget.org.

Assuming that also fails, first check curl, wget, your web browser, whatever. If those tools can access, but .NET can't, then report it to dotnet/runtime. If those tools also can't access the package source URL, then it's a problem with your networking and you need to find support elsewhere.

[zivkan]

@mrlife you didn't mention if this is your first time using dotnet, or if it previously worked and recently stopped working.

I'm wondering if there are any firewall rules, or maybe anti-virus (does mac have anti-virus?) that might be closing sockets when the app itself doesn't expect it to.

[mrlife]

@zivkan, thanks for all the suggestions. The error only seems to only be from .NET projects. I've been using .NET for years and this started maybe a year or so ago. Sometimes it's just a warning and I can build/restore. Sometimes it's an error and I'm not sure what makes it switch back from an error to a warning.

Here are my results from the suggestions:

Accessing https://api.nuget.org/v3/index.json via curl and the browser works.

Running dotnet add package DoesNotExist results with this output:

Determining projects to restore...
Writing /var/folders/2n/djygbs3j6pd2r0g_s4qps_xh_np7sx/T/tmpftsBO3.tmp
info : X.509 certificate chain validation will use the fallback certificate bundle at '/usr/local/share/dotnet/sdk/8.0.402/trustedroots/codesignctl.pem'.
info : X.509 certificate chain validation will use the fallback certificate bundle at '/usr/local/share/dotnet/sdk/8.0.402/trustedroots/timestampctl.pem'.
info : Adding PackageReference for package 'DoesNotExist' into project '/Users/UserName/MyProject/MyProject.csproj'.
error: Unable to load the service index for source https://api.nuget.org/v3/index.json.
error: Socket is not connected

Creating a new console project, updating the Program.cs, and running it results with this error:

System.Net.Sockets.SocketException (57): Socket is not connected
at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, Boolean disconnectOnFailure, String callerName)
at System.Net.Sockets.Socket.get_RemoteEndPoint()
at System.Net.Http.HttpConnectionPool.g__GetRemoteEndPoint|103_0(Stream stream)
at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.AddHttp11ConnectionAsync(QueueItem queueItem)
at System.Threading.Tasks.TaskCompletionSourceWithCancellation`1.WaitWithCancellationAsync(CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.HttpClient.g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)
at Program.

$(String[] args) in /Users/UserName/TestProject/Program.cs:line 1
at Program.(String[] args)

Should I close this issue out and reference it in a new issue in dotnet/runtime?

[zivkan]

sorry, I'm behind in my notifications. I say yes, ask in dotnet/runtime. NuGet uses HttpClient, and if the most simple "hello world" HttpClient usage doesn't work, then I as a NuGet expert can't help.

[mrlife]

@joeloff @marcpopMSFT

Hi, possible to provide any guidance, workaround, or solution for this?

[karelz]

@mrlife did you try HelloWorld style app on your machine? Can you paste the code here?
Do you have another machine to try it on? (likely not, but it is worth a shot)
Can you try the same on .NET 9.0?