1. Open Thunderbird.
2. Click the 'Tools' menu, and select 'Accounts Settings'
3. Click the Account Actions button.
4. Click Add Mail Account.
5. Enter your name as you would like it to appear on your outgoing mail messages.
6. Click your E-mail address.
7. Click your E-mail password.
8. Click the Continue button. Thunderbird will now attempt to setup account automatically. It will create an IMAP account and will not use SSL.
9. Once the automatic setup has completed, click on Advanced Config.
10. Enter the information as below.
Incoming:-
Select POP3 should you would like to create POP3 account
Server Hostname: mail.yourdomain.com
Port: 110
Outgoing:-
Server Hostname: mail.yourdomain.com
Port: 587 or 25
11. Click Create Account.
12. Under Security settings section, choose "Password, transmitted insecurely".
13. Then click on "Outgoing Server (SMTP)".
14. Highlight the email account you just created and click Edit.
15. Put your username: username@yourdomain.com
16. Then you're done.