Problem:
ATT mail not accepting password in clients like Outlook. When you hit send and receive, it comes up asking for a password you KNOW has been entered correctly.
Solution:
Worked with ATT Tech support who instructed me to get out of all email applications and login to the webmail. Log out of the web mail and try the client again, this preforms some sort of reset on the server. Email will now flow without asking for passwords.
