Hi, it seems we have a similar situation.
viewtopic.php?f=7&t=56005

Did you end up figuring out what went wrong?

Hi, I recently updated my Debian server to 11(Bullseye) and I can't seem to connect to deluge's webUI after the update. When checking services (systemctl status deluged), it's active, enabled, and running. I checked the version here : deluged --version deluged 2.0.3 libtorrent: 1.2.9.0 Python: 3.9.2...