I don’t use Plex Media Server that often, but I noticed just now that my libraries had gone. When I logged in to the server, which is on my Synology NAS, I noticed that the Seting menu had drastically changed. No more libraries, no more server settings. If I try to add media I am promted to get Plex Media Server. :-s
I removed PMS from the Synology, downloaded the latest version directly from Plex.tv and did a manual install. This did not help.
I went over to the Plex.tv webite, logged in, but cannot find anything server related.
I do have a Plex pass. Am I overlooking something?
Thanks for the quick reply! Oddly enough the issue seems to have resolved itself after stap 1 from your list.
I noticed that Plex opened using a domain name instead of a IP address. When I substituted the IP address, the server logged me out, but to my surprise also started showing the old libraries, telling me that this server needed to be claimed. After logging in and claiming the server the libraries are now visible and usable again in my account.