I had the security Q+A set up but I can only remember one answer. Neither ATT or Yahoo has a reach number to call and get this fixed.

Not me, but others report so:

https://istheservicedown.com/problems/att

https://forums.att.com/t5/AT-T-Internet-Email-Security/Cant-acess-my-email/m-p/5800149

Seems like waiting is all you can do.

I guess I'll wait until morning and see what happens.

I had to reset my password, but they never actually told me that. I had to do a lot of Googling to figure it out.

I think I clicked on the "forgot my password" link and then followed the instructions. And I did have to remember my security answers, but I always choose ones I know I'll remember like "What was the name of your first pet?" rather than "What is your favorite color?" or "What is your quest?"
.

It happened to my mom a few days ago (SBCGlobal account). AT&T won't take responsibility because she's no longer their customer, and the Yahoo "forgot my password" website routes her to AT&T.

one of their Techs walked me through resetting a new password. Once we did that - everything worked again. I just have to remember a new password. The old one I used for over 7 yrs.

Since my mom isn't an AT&T customer, they just told her the account was gone and they couldn't do anything.

The account isn't gone, since I've sent test messages to it, and they haven't bounced. But she decided to abandon Yahoo and create a Gmail account.