FaceTime activation issue on Mac with registered Apple Account

Just started this morning 12-14-24 .... attempted to make a routine FaceTime call, and was not able to contact the person I had numerous times before. Button to connect was "dead". Was able to make a phone call, strangely, though FT - but that was it. Could not FT anyone, nor add any names or numbers, either. After I shut it down, restarted computer, and tried again, I got a notification telling me to “Activate the Facetime App by signing in with your Apple ID.” I tried ... and it would just go back to the same "activate the Facetime App..." screen. Interestingly, it had my apple id showing, but not the password. Tried numerous times to no avail. I checked online with iCloud, and everything there is as it should be - I can and do login just fine. I even changed the password, and tried again after that - no luck. I also noticed that FT is telling me to "register apple id or phone number to make facetime calls" .... they are registered! I'd been using FT every week for months, but this just happened with no other changes. What gives? I saw others had the same problem ... but no resolution???

[Re-Titled by Moderator]