Can't send email wireless on a Sierra 750 Aircard with outlook 200

I just started using a Sierra 750 Aircard in my Sims slot for tmobil
wireless. I use ATT for my internet provider. I can receive ok, but cannot
send. I receive the following error message:

Task - Sending' reported error (0x80042109) : 'Outlook
is unable to connect to your outgoing (SMTP) e-mail server. If you continue
to receive this message, contact your server administrator or Internet
service provider (ISP).'

I have all my settings per http://www.wurd.com/cl_email_outlook-2003_gia.php
as suggested by ATT.

I have used these settings for WIFI and it worked correctly.

I was asked to check with your wireless provider if the SMTP port is being
blocked. It isn’t.