Can't Log in to App Store on Catalina
Mac OS Catalina 10.15.7, MacBook Pro. The App Store says I have updates available but when I click “update” I get a login prompt that will not highlight to accept my login ID. Instead “email@ATT.net” appears in gray. If I go to the next screen and enter my password, it is rejected. This is a new issue since I have been previously able to update.
I have tried all the suggested solutions such as logging out of iCloud and logging back in, logging out of the Music app and logging back in, restarting, etc. Nothing works. The app store works fine on my iPhone. I searched the keychain on the Mac for “ATT.net” in any field and can find nothing.
Edit: the "email" at att.net is some bogus address I have never used and don't recognize.
[Email Edited by Moderator]
MacBook Pro