I have Plex server on old hardware running Windows 10 with Raid1. I have a new PC with new hardware running on Windows 11. I have installed Plex server on the new PC. Everything is working on the new PC. I now stop the old Plex server but the Plex app on my TV is still trying to connect to the old Plex server. I deleted the App and re-installed but no go.
The Plex app on your TV, please tell us about it, like is it a Samsung Smart TV app, or maybe it’s an AppleTV 4K or a Roku or something?
To remove the Win 10 PMS server from your Plex account,
click this link to the the hosted web app on a desktop or laptop.
Then navigate to Settings → Authorized Devices → Server and see which servers are listed. If both your Win 10 and Win 11 servers are listed, the usual way to stop your players from using the old Win 10 server is to remove it from the list. That way it’s not associated with your Plex account anymore.