Can't communicate with qBittorrent and download clients are unavailable due to failures

Sonarr version (exact version): 4.0.2.1183
OS: Windows 11
Debug logs: sonarr issues - Pastebin.com
Description of issue: Hi there, new to Sonarr so please bear with me! Yesterday I started to get 2 errors from Sonarr - “Unable to communicate with qBittorrent. No connection could be made because the target machine actively refused it. (localhost:8080)” and “All download clients are unavailable due to failures”. I don’t know why this happened because I haven’t changed any settings on either qBittorrent or Sonarr recently (I did update qBittorrent this morning, but this shouldn’t have changed my settings, and I believe the errors were getting thrown before then anyways).

I saw some troubleshooting steps online that said that doing a full exit of Sonarr/Prowlarr would fix this, but when I did that and tried to restart the two apps, I got an Unable to Connect message from my browser - I had to restart my PC fully to get them to kick back in (and am still getting the errors as before).

Any help here would be appreciated!

I figured out the problem - it was that I hadn’t updated qBittorrent for a while, and they changed their WebUI authentication settings so that the password (which i had left blank, with “admin” as username) needs to be at least 6 characters. I changed the password to the qBittorrent default (“adminadmin”) and that seems to have resolved my issues! This can be closed.