On client devices without the new UNO interface, sign out of your Plex account and back in.
On other client devices, which have already been updated with the UNO user interface, perform ‘Reset Customization’ and pick a new default server.
https://support.plex.tv/articles/customizing-the-apps/
https://support.plex.tv/articles/customizing-the-mobile-apps-2/
That includes the default plex app, Plex Web
(Settings - Web Client - General - ‘Show Advanced’ - “Reset Customization” )
https://support.plex.tv/articles/customizing-plex-web/
