Sounds like you’ve already maybe ruled out some things, but as far as the port exhaustion question people had, you could prove that with “netstat -s” to see total number of active connections. You might also look in the qbittorrent log file for anything stands out. You might also check your router to make sure you’re not doing some weird port forward or something of that nature.
Ubuntu server can't connect to some sites when qbittorrent is running
Hey all, ran into a weird issue with my Ubuntu server running qbittorrent-nox I can’t seem to figure out....