Open Outlook 2003.
Click the Tools menu, and select E-mail Accounts.
Select “Add a new email account” and click Next
Select “POP3” or “IMAP” and click Next
In the User Information section, enter your name and your email address
In the Server Information section choose POP3 or IMAP and enter your email server address in the Incoming and Outgoing server boxes.
Your email server address is “mail.” followed by your domain-name. E.g. if your domain name is example.com you would enter mail.example.com
In the Logon Information section enter your email address into the User Name box and your password into the Password box.
Click the “More Settings” button
Click the Outgoing Server tab and tick the “My outgoing server requires authentication” box.
Click the Advanced tab and change the Outgoing server port number from “25” to “587”. Click Ok
Click Next followed by Finish.