Sonarr: Failed to authenticate download client: qBittorrent 4.2.0

[leftl]

Describe the bug
Unable to authenticate download client after updating qbittorrent-nox to 4.2.0
After reverting to 4.1.9, authentication works again. It looks like minor changes were made to the webUI on this release.

Logs

19-12-6 05:02:00.6|Warn|DownloadMonitoringService|Unable to retrieve queue and history items from qBittorrent

[v3.0.3.661] NzbDrone.Core.Download.Clients.DownloadClientAuthenticationException: Failed to authenticate with qBittorrent.
  at NzbDrone.Core.Download.Clients.QBittorrent.QBittorrentProxyV2.AuthenticateClient (NzbDrone.Common.Http.HttpRequestBuilder requestBuilder, NzbDrone.Core.Download.Clients.QBittorrent.QBittorrentSettings settings, System.Boolean reauthenticate) [0x00172] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\Download\Clients\QBittorrent\QBittorrentProxyV2.cs:384 
  at NzbDrone.Core.Download.Clients.QBittorrent.QBittorrentProxyV2.ProcessRequest (NzbDrone.Common.Http.HttpRequestBuilder requestBuilder, NzbDrone.Core.Download.Clients.QBittorrent.QBittorrentSettings settings) [0x00000] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\Download\Clients\QBittorrent\QBittorrentProxyV2.cs:290 
  at NzbDrone.Core.Download.Clients.QBittorrent.QBittorrentProxyV2.ProcessRequest[TResult] (NzbDrone.Common.Http.HttpRequestBuilder requestBuilder, NzbDrone.Core.Download.Clients.QBittorrent.QBittorrentSettings settings) [0x00000] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\Download\Clients\QBittorrent\QBittorrentProxyV2.cs:283 
  at NzbDrone.Core.Download.Clients.QBittorrent.QBittorrentProxyV2.GetConfig (NzbDrone.Core.Download.Clients.QBittorrent.QBittorrentSettings settings) [0x00012] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\Download\Clients\QBittorrent\QBittorrentProxyV2.cs:82 
  at NzbDrone.Core.Download.Clients.QBittorrent.QBittorrent.GetItems () [0x00000] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\Download\Clients\QBittorrent\QBittorrent.cs:125 
  at NzbDrone.Core.Download.TrackedDownloads.DownloadMonitoringService.ProcessClientDownloads (NzbDrone.Core.Download.IDownloadClient downloadClient) [0x0000c] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\Download\TrackedDownloads\DownloadMonitoringService.cs:90

This will repeat until the qBittorrent bans my Sonarr host.

System Information

• Sonarr Version: 3.0.3.661
• Operating System: Debian 10 (Buster)
• .net Framework (Windows) or mono (macOS/Linux) Version: 5.20.1.34

[markus101]

Pretty sure they changed something with their authentication and it requires you to re-enter your password in qbittorrent or all connections fail.

Is there anything in their changelog about what they changed?

They have a tendency to make breaking changes without warning, it’s a PITA to support that.

[Taloth]

Their changelog states:

WEBUI: Use PBKDF2 for the WebUI password. You will need to set your password again.

From Sonarr reddit/discord:

Instead of just setting a new password, stop qB, edit the config file and remove the password line that starts like WebUI\Password_PBKDF2=. Then start it up again, the default password is adminadmin. Now change the password again, save and restart.

It's weird that they're not handling the old pwd algo automatically, but it's not something we can address.

[mrwebsmith]

i believe this same issue is occurring for me just now... and this conf line fix and reset password DID NOT work out at this point.

anyone else seeing this?

qbt: 4.2.1 (x64)
sonarr: 3.0.0.348