One of two Plex servers disappeared from app and plex.tv

[tom80H]

Best start here:
https://support.plex.tv/articles/204281528-why-am-i-locked-out-of-server-settings-and-how-do-i-get-in/

There’s some hints on claiming a Linux server (especially after there’s been issues)

Linux Tips

When server and device credentials are out of sync. Use this procedure when: You receive the nasty “No Soup For You” message You’ve changed your Plex password and now have trouble accessing something. You’ve cloned the server or performed a ‘backup & restore’ using the procedures above but now cannot access the server. First choice - Preferences.xml missing or deleted. If something happened to “Preferences.xml” and you need to claim the server again, with everything being normal, Start he…