ATT IMAP email connection quit working on iPhone 12 this week

... has been sporadic on iMac, and IPad. Web based email via Yahoo and Mac Mail on MacBook Pro still working normally. I'm following the recommendations here to delete account and re-install. I get to the sign on screen for the IMAP setup and this box appears: "no password provided for <user>@sbcglobal.net. Please go to Mail Account Settings and enter a password" Can't get past that. Could I be locked out? How can I tell? I've tried both the Yahoo quick set up and the "Other" route direct to ATT servers. Thanks!