Unable to reinstall AT&T email account on iPhone XR after updating password

I had attempted to login to my AT&T email account on my computer and kept getting a message that my user ID or password were incorrect, they were not. To avoid trying too many times and having account on hold, I clicked on Forgot password to reset it. However, I reset it with the same password I've been using.

In order to update the password on my phone I had to delete if first and then add it back. I am unable to do so and so were two different Apple techs. We tried to reinstall it 25-30 times and each time it said password or username was wrong.

1. Mail > Add Account > selected other since AT&T is not one show
2. Add Mail Account - added my name, my email address xxxx@att.net, and entered password
3. Clicked Next to verify it and that's when I get the message Wrong username and/or password provided. Please go to Mail Account Settings and enter the correct username and password

We even tried selecting Yahoo from the list of accounts since Yahoo took over managing AT&T's emails. We entered the email address as xxxx@ leaving off att.net to see if that would work. It didn't.

Do I need to resert the password with AT&T again since I used the same password I had been using? I'm cautious of doing that because at one point I couldn't get into my AT&T email (two different accounts) on my computer yesterday. The login screen wouldn't even come up "Something went wrong" message. After several attempts to get through to AT&T I finally connected with someone who said it may take 7 days to resolve the issue and someone would call me back (yeah right). I was able to access my email on my computer this morning, but still can install it back on my phone.

Any suggestions would be greatly appreciated.

[Re-Titled by Moderator]