Go to the AT&T Password Reset page in your computer's web browser.
Fill in the blank fields in the "Find your password" window with your User ID and last name, then enter the button of "Continue."
To obtain a temporary password, you can now choose between text and email.
Click the button of ‘Continue' after entering the temporary password in the given text field.
You can now create a new password for your Bellsouth email account, which you can use for all future logins.
See Also this post:- https://datarecovo.mypixieset.com/blog/how-to-fix-bellsouth-email-login-error/