The servers for all legacy BellSouth pop accounts are:

Incoming mail server type: POP3

Incoming (POP): pop.att.yahoo.com

Outgoing (SMTP): smtp.att.yahoo.com (requires authentication)

Incoming/Outgoing User Name: Full AT&T email address, including domain (i.e. name@bellsouth.net)

Incoming mail port #: 995, secure connection (SSL) checked
Outgoing mail port # 465, secure connection (SSL) checked