iMessages freezes and resets to sign at launch.

I am on a 2019 MacBook Pro, upgraded to Tahoe 26.0.1 Messages worked perfectly up till a month ago. Over night it started at launch to ask me to sign in. When I did, it would launch and display text from Sept. then after 15 - 20 seconds, it would reset and ask me to sign in again. I've restarted, restarted in safe mode, updated to Tahoe (was hoping that would fix it, but nope) searched support files for clues but have not found a solution. Any Ideas?