Dec 09 21:28:39 jelly jellyfin[17394]: [21:28:39] [ERR] Error processing request. URL POST /Users/AuthenticateByName. Dec 09 21:28:39 jelly jellyfin[17394]: System.ArgumentNullException: Value cannot be null. (Parameter 'request.App')
Jellyfin 10.11.4 infusesync 1.5.2.0 Diag info: AC1NV / #183477
I am seeing this as well. Only thing that works is removing the Jellyfin server and re-adding.
Latest Infuse Sync and Jellyfin in Library mode.
A number of improvements for connecting to Emby and Jellyfin servers are available in today’s 8.3.7 update.
Please let us know if you continue to see any issues here.