Over 1 month after original post on this thread and I am still having this issue. The issue started when ios 14.3 loaded on both mine and my wife's phones; therefore it is most likely something related to ios 14.3 rather than mass mail server failures on 12-15-2020. I have deleted and re-added the mail accounts multiple times to no avail. I have restarted the phones multiple times. I am in over my head now as I am NOT a tech oriented person. If anyone has a solution I would be forever grateful!!! Thank you!
Update, after spending a total of roughly 12 hours over the last 2 days my issue has resolved. It is still a strange solution, but it worked. Here is what worked for me:
1. Log in to att.com site and choose the sub-account you are having issues with (I only have the one account)
2. Verify your email address on acct. in question
3. Verify a separate email account as a recovery account
4. Verify your mobile # for recovery
5. On iPhone (ios 14.3) delete the mail account in question
6. Choose to add a new account and setup using the Yahoo! option
7. Enter your username which is the email address you are adding
8. THIS IS THE MOST IMPORTANT STEP!!! As crazy as this sounds, your account will not work if you do not do this! When asked to add the password, while setting up the account using the Yahoo! wizard,
enter an incorrect password, yes enter an incorrect password!!! You have to do this, I can't stress this enough!
9. After entering your username and incorrect password, re-enter your username and the correct password and save
10. Make sure to disable all services except for "mail" and verify
You should be good to go now!
I hope this helps, and if you get an error 205.4 when trying to login on att.com, just keep trying. It took multiple attempts over the course of a couple of hours today and then Poof! I was magically logged in. Not sure what changed, but you know how it goes, don't look a gift horse in the mouth! Good luck!
