[Puterguru]

This should fix the problem:

If using Outlook Express:
Click on Tools
Click on Accounts
Click on your mail account so that it is highlighted
Click on the properties button to the right
Click on the Advanced tab
Directly next to "Outgoing Mail(SMTP) change the number that is there (probably 25) to the number 587.
Click on Apply
Click on OK
Click on Close
Close Outlook Express

Re-open Outlook Express and try to send some messages. I bet they'll go thru.