Server log files needed.
If Plex is running, go to Settings → Troubleshooting. Download the logs and attach the entire zip file to the thread.
If Plex is not running, using Synology File Station, navigate to the Plex Data Folder. Right click on the Logs directory, choose compress to logs.zip. Attach the zip file to the thread.
See Synology FAQ 1: Gaining access to the Plex logs or when PMS isn’t running / won’t start
