Check that AT&T Mail Outlook settings is correctly configured.
Check that your antivirus software is up to date.
Use IMAP server, instead of POP server settings.
First remove then re-add your email profile
In Safe Mode open outlook account.
Always use Google DNS
Use Webmail account always.
Following are the best steps to Att email is not working on Outlook.
See Also this post:- https://www.datarecovo.com/att-email-settings-for-outlook/
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