Outlook and Outlook Express

1. From the menu, select Account Settings / Email Accounts
   
2. Highlight your Mail account and edit the properties
   
3. Click the More Settings button
   
4. Choose the Outgoing Server tab.
   
5. Check the box next to My Outgoing Mail server requires authentication.
   
6. Click the Apply button.
   
7. Click the OK button.

Macintosh

1. For SMTP Authentication, make sure that you have Outlook Express 5.02, then...
   
2. Open the configured account that is having issues...
   
3. Go to the servers tab.
   
4. At the bottom of the box you will see a 'click here for advance sending options' button.
   
5. Click this button.
   
6. When the dialog box opens, click the 'SMTP server requires authentication' check box.
   
7. By default, the 'Use same settings as incoming mail server' button is clicked.
   
8. Check 'Log on using' instead of 'Use same settings as incoming mail server.'
   
9. In the account ID box, enter your Account as you email address, but instead of the '@' sign, use the '&' sign.