How to add E-Mail Authentication in Outlook 2007:
 
1. Open Outlook.
 
2. Click on Tools in the toolbar and then click on Account Settings....
 


3.  E-mail Accounts

     - Click the E-mail tab
     - Left click the e-mail account you wish to modify to highlight it
     - Click the Change... button
 


4.
Internet E-mail Settings

     - Verify all information is correct
     - Click the More Settings... button
 


5.
Click on the Outgoing Server tab.

     - put a check in the My outgoing server (SMTP) requires authentication
    
- Select the Use same settings as my incoming mail server radio button

     Click the OK button
 

 
6.
Click the Finish button