This thread might have info that can help: New update 1.32.8.7639 crashing randomly on synology nas
Pull the server log files (Settings → Troubleshooting). Unzip. Look in Plex Media Server.log (and .1.log to .5.log) for ERROR entries that mention the database is malformed or corrupt.
If the db is corrupt, run the Plex DBRepair Utility: GitHub - ChuckPa/PlexDBRepair: Database repair utility for Plex Media Server databases. Use the AUTO option.
If the problem lies elsewhere, then upload the ZIP with the logs and someone can take a look.
Regarding reverting to a previous release, Synology does not permit direct downgrades. Uninstall Plex Media Server, selecting the “Uninstall Only” option. Then install the desired version. Initial startup may take longer due to database adjustments between releases. If you see a “503 server maintenance” message when trying to login to the server, wait a few minutes and try again.
