rafe, This completely derailed all of my productivity as I tried to fix it. Couldn't even verify my identity for a while due to server errors. Took over an hour, plus a call to a totally useless Support agent who blew me off and kept insisting that I had just forgotten my password, before I finally got back in on my own.
https://www.macrumors.com/2024/04/27/apple-id-accounts-logging-out-users/