Outlook XP / 2003

1. "Tools" / "Email Accounts"

2. "View or change existing email accounts" and click "Next"

3. Your email account appears, usually labeled "mail.yourdomain.com"

4. Click on your email account and click the "Change" button on the right

5. Under the "Server Information" section, Click the button "More Settings..." in the lower right-hand corner.

6. Click the "Outgoing Server" tab.

7. Check "My outgoing server (SMTP) requires authentication", and "Use same settings as my incoming mail server"

8. Change SMTP Port to 587 (Originally "25")

9. "OK" and close