I’ve had this same issue on my last two updates of PMS on my QNAP device.
After updating PMS in the App Center, the service shows as running but is not accessible and when looking in the logs I see the error message above in the original post.
I have then attempted to stop and start the service via the App Center and this still does not resolve the issue.
When investigating further via SSH, even when the service shows stopped I can still see the process binding to the port using netstat:
[~] # netstat -lpn | grep 32400
tcp 26 0 :::32400 :::* LISTEN 29322/Plex Media Se
After killing this PID, I am able to restart PMS without any issues.
I suspect something has changed in the update script that results in the previous version not stopping correctly.
