cannot mark anything as watched unwatched. Unknown error!

cannot mark anything as watched unwatched. Unknown error!
No idea how to fix it.
latest server. Mac OS

  1. activate debug logging (not ‘verbose’!)
  2. quit Plex Server
  3. wait 1 minute
  4. start Plex Server
  5. wait 5 minutes
  6. fetch log files and attach them here

Or inspect them yourself. Take a look at the Plex Media Server.log file and seek for messages about database corrupt or malformed.
If you find these, you may have to repair your database.
https://support.plex.tv/hc/en-us/articles/201100678-Repair-a-Corrupt-Database