Choose the options of File then Select the options of Add Account in Outlook.
Choose between manual configuration and additional server forms.
Choose between Pop and IMAP.
Complete the following fields in your user profile
Complete the following fields on the server
Complete all the login information
Click on More Options.
Follow above mentioned steps to set up ATT Email in outlook.
See Also this post:- https://blog.storymirror.com/read/8cuycvkb/at-t-email-not-working-here-s-how-to-fix-all-errors