Launch Outlook XP and make sure it is the active window on your desktop. Then do the following.

1. From the Tools menu, select (click) Email Accounts...
2. In the "E-mail Accounts" dialog box:
   1. Check View or change existing e-mail accounts
   2. Click the Next button.
   3. Select the email account to be SMTP-authenticated.
   4. Click the Change… button.
   5. Click the More Settings… button.
3. In the "Internet E-mail Settings" dialog box:
   1. Click the Outgoing Server tab.
   2. Check My outgoing server (SMTP) requires authentication
   3. Check Use same settings as my incoming mail server
   4. Click OK to close the "Internet E-mail Settings" dialog box.
4. In the "E-mail Accounts" dialog box click the Next> button and then click the Finish button.