It means that the web app couldn’t get a connection to your plex server.
They are technically separate components.
It appears your server is not signed into your plex account.
maybe it is already signed into an other account? This happens often if it was already installed on this computer before, but the used account credentials were forgotten.
Use this procedure to clear out the old account info for plex server from your system.
Make sure to follow all the steps exactly.
