If you have an e-mail account at AT&T such as domains ending with @att.net, @bellsouth.net or @sbcglobal.net, you might have been receiving repeated “Enter Network Password” prompts in Outlook any version.
This could also happen in a mail client other than Outlook as it appears that there has been a recent change to their mail server configuration. To solve it, try the following:
Login to AT&T Webmail to make sure your password is still valid. In some rare cases, logging on to your Webmail once already fixes the issue. If not, use Yahoo’s mail server settings instead of AT&T’s.
POP3: pop.mail.yahoo.com SSL: EnabledPort: 465
SMTP: smtp.mail.yahoo.com SSL: EnabledPort: 995