Did you use Plex server on this PC before, under a different plex account?
If you did, use this procedure to change the plex account under which the server is operating: You need to reclaim your server, but don't dare to touch the Windows Registry
Btw, change your Plex password. Accounts with Plex Pass are a juicy target for account thieves. Important notice of a potential data breach 24th of August 2022
