It appears your server is alive and well.
Your Plex app might not be allowed to access it, though.
Perform this procedure to restore access to it from the Web app: https://support.plex.tv/articles/204281528-why-am-i-locked-out-of-server-settings-and-how-do-i-get-in/
I don’t see a Samsung TV in your Plex account, so it might simply not be attached to your plex.tv account.
Or it might be an old device (model year 2015 and older) which is now no longer compatible with plex.tv Samsung TV Cannot Connect to Plex
