Web Login Error: After a few days of PVE 9 running, logins to the PVE Web UI fail (401 error) until I change the password

hive

Member
Mar 6, 2021
12
2
23
59
I'm running a standalone PVE 9.0.11 on a remote host connected with tailscale (no ports open to the interwebs).

After the server has been running for a few days, when I try to login to the web UI, I get a 401 authentication error.
I've noticed that when this occurs, my nightly backups to a remote PBS machine have stopped being sent to the PBS machine.

I can still ssh to the box (using tailscale ssh), and I can su to root using the same root password that fails to authenticate in the web UI.
If I reset my root password, and restart the PVE box, login to the web UI starts working again.

Has anyone else experienced this? Do you have a fix?
What log files would you suggest I look at to try to diagnose the root cause?