Click on the tools tab at the top of the program window then click on Email Accounts.
Select Add New Email Account, click Next
Choose POP3 as your server type by clicking the radio button, and click Next.
Fill in all necessary fields:
User Information Your Name: Enter your name as you would like it to appear in the from field of outgoing messages. Email Address: Enter your full email address (username@yourdomain.com).
Server Information Incoming Mail Server (POP3): mail.yourdomain.com Outgoing Mail Server (SMTP): mail.yourdomain.com
Login Information User Name: Enter your user name of the account (including @yourdomain.com) Password: Enter your account password
Click More Settings... and then click the Outgoing Server tab.
Check the box next to My outgoing server (SMTP) requires authentication and select Use same settings as my incoming mail server.
Click Test Account Settings... After receiving Congratulations! All tests completed successfully, click Close.