While a server upgrade is in process, the Server → Settings → General page indicates:
This server is unclaimed and not secure
Claiming this server will associate it with your Plex account. This helps your devices find each other and helps keep your media safe.
This is incorrect and needlessly worrisome - since the actual situation being encountered, is that the server is not currently active, while the upgrade is taking place.
Can the development team modify this warning to recognize this situation, and not make users paranoid while such an upgrade is progressing?
To clarify: As soon as the server upgrade is complete, it (correctly) recognizes that I am still logged in, and the server is associated with my account - with no other interactions being necessary.
The fact that the “unclaimed” message appears in the middle of that software upgrade process, is what needs to be addressed.
Discussions get labelled answered as soon as there is a comment, it should really say responded to rather than answered as many comments are not answers as such. Only the Green Accepted Answer indicates that the OPer thinks that it has been answered.