AT&T Internet Service Provider Email Problems
AT&T has restricted outgoing email by directing all SMTP traffic to their servers only. This is to reduce spam, but it makes it very hard to use Outlook or any other mail program to send email if you have Uverse or DSL thru AT&T. There is a way around this though. Most SMTP servers also accept mail on port 587. Try changing the outgoing mail to port 587. You may get lucky if your email host accepts email on that port. Don’t forget to tell Outlook to use the same name and password as your incoming (POP) server.