[BUG] Can not log in when using Firefox

[peterG0RSQ]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

At login page, enter user (admin) and password (found in log file) then login page reverts back to login page. Works OK in Microsoft edge.
However if you put slash at end of URL "http://192.168.11.102:8080/" followed by "return" it logs in without entering user or password in firefox

Expected Behavior

should login with correct user/password.

Steps To Reproduce

run WEBUI from docker to get login page

Environment

firefox 146.0 64 bit
Windows 11 latest on client
UNRAID 7.1.4
qBittorrent v5.1.4 WebUI (64-bit)- OS:

Docker installed through apps tab. All standard container settings except network type and files location.

CPU architecture

x86-64

Docker creation

GID/UID
───────────────────────────────────────

User UID:    99
User GID:    100
───────────────────────────────────────
Linuxserver.io version: 5.1.4-r1-ls431
Build-date: 2025-12-07T06:57:16+00:00
───────────────────────────────────────
    
[custom-init] No custom files found, skipping...
WebUI will be started shortly after internal preparations. Please wait...

******** Information ********
To control qBittorrent, access the WebUI at: http://localhost:8080
[ls.io-init] done.
[migrations] started
[migrations] no migrations found
usermod: no changes

Container logs

(N) 2025-12-14T23:13:53 - qBittorrent v5.1.4 started. Process ID: 176
(N) 2025-12-14T23:13:53 - Using config directory: /config/qBittorrent
(N) 2025-12-14T23:13:53 - Trying to listen on the following list of IP addresses: "0.0.0.0:6881,[::]:6881"
(I) 2025-12-14T23:13:53 - Peer ID: "-qB5140-"
(I) 2025-12-14T23:13:53 - HTTP User-Agent: "qBittorrent/5.1.4"
(I) 2025-12-14T23:13:53 - Distributed Hash Table (DHT) support: ON
(I) 2025-12-14T23:13:53 - Local Peer Discovery support: ON
(I) 2025-12-14T23:13:53 - Peer Exchange (PeX) support: ON
(I) 2025-12-14T23:13:53 - Anonymous mode: OFF
(I) 2025-12-14T23:13:53 - Encryption support: ON
(I) 2025-12-14T23:13:53 - Successfully listening on IP. IP: "127.0.0.1". Port: "TCP/6881"
(I) 2025-12-14T23:13:53 - Successfully listening on IP. IP: "127.0.0.1". Port: "UTP/6881"
(I) 2025-12-14T23:13:53 - Successfully listening on IP. IP: "192.168.11.102". Port: "TCP/6881"
(I) 2025-12-14T23:13:53 - Successfully listening on IP. IP: "192.168.11.102". Port: "UTP/6881"
(I) 2025-12-14T23:13:53 - Successfully listening on IP. IP: "::1". Port: "TCP/6881"
(I) 2025-12-14T23:13:53 - Successfully listening on IP. IP: "::1". Port: "UTP/6881"
(W) 2025-12-14T23:13:53 - Couldn't load IP geolocation database. Reason: No such file or directory
(N) 2025-12-14T23:13:53 - Using built-in WebUI.
(W) 2025-12-14T23:13:53 - Couldn't load WebUI translation for selected locale (C).
(N) 2025-12-14T23:13:53 - WebUI: Now listening on IP: *, port: 8080
(I) 2025-12-14T23:13:53 - Detected external IP. IP: "2.103.47.191"
(I) 2025-12-14T23:13:53 - IP geolocation database loaded. Type: DBIP-Country-Lite. Build time: Mon Dec 1 02:28:10 2025.
(I) 2025-12-14T23:13:53 - Successfully updated IP geolocation database.
(W) 2025-12-14T23:15:30 - WebAPI login failure. Reason: invalid credentials, attempt count: 1, IP: ::ffff:192.168.11.110, username: admin
(N) 2025-12-14T23:16:08 - WebAPI login success. IP: ::ffff:192.168.11.110
(N) 2025-12-14T23:16:52 - qBittorrent termination initiated
(N) 2025-12-14T23:16:52 - Saving resume data completed.
(N) 2025-12-14T23:16:52 - BitTorrent session successfully finished.
(N) 2025-12-14T23:16:52 - qBittorrent is now ready to exit
(N) 2025-12-14T23:16:56 - qBittorrent v5.1.4 started. Process ID: 170
(N) 2025-12-14T23:16:56 - Using config directory: /config/qBittorrent
(N) 2025-12-14T23:16:56 - Trying to listen on the following list of IP addresses: "0.0.0.0:6881,[::]:6881"
(I) 2025-12-14T23:16:56 - Peer ID: "-qB5140-"
(I) 2025-12-14T23:16:56 - HTTP User-Agent: "qBittorrent/5.1.4"
(I) 2025-12-14T23:16:56 - Distributed Hash Table (DHT) support: ON
(I) 2025-12-14T23:16:56 - Local Peer Discovery support: ON
(I) 2025-12-14T23:16:56 - Peer Exchange (PeX) support: ON
(I) 2025-12-14T23:16:56 - Anonymous mode: OFF
(I) 2025-12-14T23:16:56 - Encryption support: ON
(I) 2025-12-14T23:16:56 - Successfully listening on IP. IP: "127.0.0.1". Port: "TCP/6881"
(I) 2025-12-14T23:16:56 - Successfully listening on IP. IP: "127.0.0.1". Port: "UTP/6881"
(I) 2025-12-14T23:16:56 - Successfully listening on IP. IP: "192.168.11.102". Port: "TCP/6881"
(I) 2025-12-14T23:16:56 - Successfully listening on IP. IP: "192.168.11.102". Port: "UTP/6881"
(I) 2025-12-14T23:16:56 - Successfully listening on IP. IP: "::1". Port: "TCP/6881"
(I) 2025-12-14T23:16:56 - Successfully listening on IP. IP: "::1". Port: "UTP/6881"
(I) 2025-12-14T23:16:56 - IP geolocation database loaded. Type: DBIP-Country-Lite. Build time: Mon Dec 1 02:28:10 2025.
(N) 2025-12-14T23:16:56 - Using built-in WebUI.
(W) 2025-12-14T23:16:56 - Couldn't load WebUI translation for selected locale (C).
(N) 2025-12-14T23:16:56 - WebUI: Now listening on IP: *, port: 8080
(I) 2025-12-14T23:16:56 - Detected external IP. IP: "2.103.47.191"
(W) 2025-12-14T23:17:34 - WebAPI login failure. Reason: invalid credentials, attempt count: 1, IP: ::ffff:192.168.11.110, username: admin
(N) 2025-12-14T23:23:49 - WebAPI login success. IP: ::ffff:192.168.11.110
(N) 2025-12-14T23:27:42 - WebUI translation for selected locale (en) has been successfully loaded.
(N) 2025-12-14T23:28:48 - WebAPI login success. IP: ::ffff:192.168.11.110
(N) 2025-12-14T23:32:32 - WebAPI login success. IP: ::ffff:192.168.11.110
(N) 2025-12-14T23:40:38 - qBittorrent termination initiated
(N) 2025-12-14T23:40:38 - Saving resume data completed.
(N) 2025-12-14T23:40:38 - BitTorrent session successfully finished.
(N) 2025-12-14T23:40:38 - qBittorrent is now ready to exit
(N) 2025-12-14T23:41:35 - qBittorrent v5.1.4 started. Process ID: 173
(N) 2025-12-14T23:41:35 - Using config directory: /config/qBittorrent
(N) 2025-12-14T23:41:35 - Trying to listen on the following list of IP addresses: "0.0.0.0:6881,[::]:6881"
(I) 2025-12-14T23:41:35 - Peer ID: "-qB5140-"
(I) 2025-12-14T23:41:35 - HTTP User-Agent: "qBittorrent/5.1.4"
(I) 2025-12-14T23:41:35 - Distributed Hash Table (DHT) support: ON
(I) 2025-12-14T23:41:35 - Local Peer Discovery support: ON
(I) 2025-12-14T23:41:35 - Peer Exchange (PeX) support: ON
(I) 2025-12-14T23:41:35 - Anonymous mode: OFF
(I) 2025-12-14T23:41:35 - Encryption support: ON
(I) 2025-12-14T23:41:35 - Successfully listening on IP. IP: "127.0.0.1". Port: "TCP/6881"
(I) 2025-12-14T23:41:35 - Successfully listening on IP. IP: "127.0.0.1". Port: "UTP/6881"
(I) 2025-12-14T23:41:35 - Successfully listening on IP. IP: "192.168.11.102". Port: "TCP/6881"
(I) 2025-12-14T23:41:35 - Successfully listening on IP. IP: "192.168.11.102". Port: "UTP/6881"
(I) 2025-12-14T23:41:35 - Successfully listening on IP. IP: "::1". Port: "TCP/6881"
(I) 2025-12-14T23:41:35 - Successfully listening on IP. IP: "::1". Port: "UTP/6881"
(I) 2025-12-14T23:41:35 - IP geolocation database loaded. Type: DBIP-Country-Lite. Build time: Mon Dec 1 02:28:10 2025.
(N) 2025-12-14T23:41:35 - Using built-in WebUI.
(N) 2025-12-14T23:41:35 - WebUI translation for selected locale (en) has been successfully loaded.
(N) 2025-12-14T23:41:35 - WebUI: Now listening on IP: *, port: 8080
(I) 2025-12-14T23:41:35 - Detected external IP. IP: "2.103.47.191"
(N) 2025-12-14T23:41:49 - qBittorrent termination initiated
(N) 2025-12-14T23:41:49 - Saving resume data completed.
(N) 2025-12-14T23:41:49 - BitTorrent session successfully finished.
(N) 2025-12-14T23:41:49 - qBittorrent is now ready to exit
(N) 2025-12-14T23:41:53 - qBittorrent v5.1.4 started. Process ID: 170
(N) 2025-12-14T23:41:53 - Using config directory: /config/qBittorrent
(N) 2025-12-14T23:41:53 - Trying to listen on the following list of IP addresses: "0.0.0.0:6881,[::]:6881"
(I) 2025-12-14T23:41:53 - Peer ID: "-qB5140-"
(I) 2025-12-14T23:41:53 - HTTP User-Agent: "qBittorrent/5.1.4"
(I) 2025-12-14T23:41:53 - Distributed Hash Table (DHT) support: ON
(I) 2025-12-14T23:41:53 - Local Peer Discovery support: ON
(I) 2025-12-14T23:41:53 - Peer Exchange (PeX) support: ON
(I) 2025-12-14T23:41:53 - Anonymous mode: OFF
(I) 2025-12-14T23:41:53 - Encryption support: ON
(I) 2025-12-14T23:41:53 - IP geolocation database loaded. Type: DBIP-Country-Lite. Build time: Mon Dec 1 02:28:10 2025.
(N) 2025-12-14T23:41:53 - Using built-in WebUI.
(N) 2025-12-14T23:41:53 - WebUI translation for selected locale (en) has been successfully loaded.
(N) 2025-12-14T23:41:53 - WebUI: Now listening on IP: *, port: 8080
(I) 2025-12-14T23:41:53 - Successfully listening on IP. IP: "127.0.0.1". Port: "TCP/6881"
(I) 2025-12-14T23:41:53 - Successfully listening on IP. IP: "127.0.0.1". Port: "UTP/6881"
(I) 2025-12-14T23:41:53 - Successfully listening on IP. IP: "192.168.11.102". Port: "TCP/6881"
(I) 2025-12-14T23:41:53 - Successfully listening on IP. IP: "192.168.11.102". Port: "UTP/6881"
(I) 2025-12-14T23:41:53 - Successfully listening on IP. IP: "::1". Port: "TCP/6881"
(I) 2025-12-14T23:41:53 - Successfully listening on IP. IP: "::1". Port: "UTP/6881"
(I) 2025-12-14T23:41:53 - Detected external IP. IP: "2.103.47.191"
(N) 2025-12-14T23:42:12 - WebAPI login success. IP: ::ffff:192.168.11.110

[github-actions]

Thanks for opening your first issue here! Be sure to follow the relevant issue templates, or risk having this issue marked as invalid.

[peterG0RSQ]

Further information on issue

Now I have a password saved, you can log in normally once (first time) but subsequent attempts to log in show symptoms described.
Stopping and restarting the container makes no difference.
Sorry new to UNRAID and Docker so I hope I am clear.

[j0nnymoe]

This is less likely to be a container issue but more to be specific to qbittorrent itself or an extension/config issue with your firefox install, as you've proven it works fine in Edge.

Worth trying a private browser window of firefox.

[Giggitybyte]

I am also experiencing this issue. Firefox 146.0.1 installed through Snap. Leading up to this, the container would crash and restart inconsistently every 5-30 minutes for the past day. I have Caddy acting as a reverse proxy to this container.

I disabled all extensions and cleared all cookies for my domain, and I am unable to login.
I tried twice with a fresh install of this container and I am unable to login.

Logs:

qbittorrent  | [migrations] started
qbittorrent  | [migrations] no migrations found
qbittorrent  | ───────────────────────────────────────
qbittorrent  | 
qbittorrent  |       ██╗     ███████╗██╗ ██████╗
qbittorrent  |       ██║     ██╔════╝██║██╔═══██╗
qbittorrent  |       ██║     ███████╗██║██║   ██║
qbittorrent  |       ██║     ╚════██║██║██║   ██║
qbittorrent  |       ███████╗███████║██║╚██████╔╝
qbittorrent  |       ╚══════╝╚══════╝╚═╝ ╚═════╝
qbittorrent  | 
qbittorrent  |    Brought to you by linuxserver.io
qbittorrent  | ───────────────────────────────────────
qbittorrent  | 
qbittorrent  | To support LSIO projects visit:
qbittorrent  | https://www.linuxserver.io/donate/
qbittorrent  | 
qbittorrent  | ───────────────────────────────────────
qbittorrent  | GID/UID
qbittorrent  | ───────────────────────────────────────
qbittorrent  | 
qbittorrent  | User UID:    1000
qbittorrent  | User GID:    1000
qbittorrent  | ───────────────────────────────────────
qbittorrent  | Linuxserver.io version: 5.1.4-r1-ls432
qbittorrent  | Build-date: 2025-12-21T07:00:33+00:00
qbittorrent  | ───────────────────────────────────────
qbittorrent  |     
qbittorrent  | [custom-init] No custom files found, skipping...
qbittorrent  | WebUI will be started shortly after internal preparations. Please wait...
qbittorrent  | 
qbittorrent  | ******** Information ********
qbittorrent  | To control qBittorrent, access the WebUI at: http://localhost:8661
qbittorrent  | The WebUI administrator username is: admin
qbittorrent  | The WebUI administrator password was not set. A temporary password is provided for this session: 5yr5Vcj8H
qbittorrent  | You should set your own password in program preferences.
qbittorrent  | Connection to localhost (127.0.0.1) 8661 port [tcp/*] succeeded!
qbittorrent  | [ls.io-init] done.

This was after attempting to login.

[Giggitybyte]

Strangely, I tried adding a forward slash to the end of my domain as the OP mentioned, and I was instantly logged in. I enabled all my extensions and logged out, and I was able to log back in without issue. I have no idea what happened here.

[Giggitybyte]

Seems I celebrated too soon. This issue is still persisting for me. Adding a forward slash allows me to login, but as mentioned by the OP, it seems to break after a while.

[j0nnymoe]

Unable to replicate using Firefox 142.0 (Including forks of Zen/Waterfox).
Was on 5.1.2, updated qbittorrent to 5.1.4, still couldn't get it to trigger.

[kyonlion]

I am having this same problem with Librewolf 146.0.1-1 on Arch/EndeavourOS, but I didn't have this issue while using Librewolf on Windows 10. Adding a forward slash instantly logs in, consistent with previous comments.

[montusama]

I'm having the same problem as well. Updated to Latest for Qbittorrent, though wasn't paying attention to what I was running before. This is on Unraid. Firefox Private Window fixes it. I haven't attempted the forward slash yet.

[j0nnymoe]

This isn't a container problem, this will be specific to your browsers addon's/cache. Something you need to look up within qbittorrents repo issue list.

[ezgoodnight]

My issue is also the one that OP and others are having here. I am glad I checked here after assuming every part of my setup was wrong only to find the browser seems to be at fault.

Clearing cache, disabling privacy addons does not change anything. I'm using Waterfox from the Flatpak in Ubuntu.

Logging in with correct password just reloads the WebUI login page. If I do the "add slash and hit enter" thing they're saying it does indeed take me to the WebUI.

Private browser window does indeed work.

It opens in Chromium on my system. I opened Firefox (snap) for the first time in a while and it worked WITH the same addons as my Waterfox. Your guess is as good as mine, there.

A few days ago I had a similar login issue with Cockpit where the issue was linking from HTTP Heimdall to Cockpit. I am curious if setting up HTTPS for this web UI will fix this issue. For now there are workarounds but I was going insane trying to figure out why this was happening.

Update: Got the same bug in Waterfox for Windows. Clearing the cookies for the whole server did indeed fix the issue there. I swear this did not work on my Ubuntu machine but now I'm doubting myself.