Chuck, please take a look into this. This seems to match: Plex server is running but not accessible
The issue lies in the systemd startup script. Running commands separate, plex works normally.
Fixed: It looks like privileges were either affected through the update or through apt upgrade (I doubt this).
Simply roll privileges of plex’s home directories to your allocated “plex” user or change the systemd startup script’s user and group. The latter is easier, but poses security risks.
Some thoughts: Plex doesn’t check privilege level when trying to log. This made it very difficult to debug a small issue since logs could not be written. No verbosing either through direct binary runs.
