To configure your mail account in Mozilla, you need to follow
below mentioned guide lines:

1. Launch Mozilla

    From the Window menu, select Mail & Newsgroups.
    The Mail & Newsgroups window appears.
    From the Edit menu, select Mail & Newsgroups Account Settings....
    The Mail & Newsgroups Account Settings window appears.

2. Click Add Account....The Account Wizard appears.

3. Select E-mail account.
    Click Next.

4. Enter the username in the Your Name field. This is the name that will appear
    in the From field of the messages that are sent from this account.
    Enter the e-mail address in the E-mail Address field:
    username@yourdomainname.com
    Click Next.

5. Select the e-mail protocol you want to use.
    Select POP3
    Enter the hostname of your e-mail server in the Incoming Server field:
     mail.yourdomainname.com
    Click Next.

6. In the User Name field, enter the complete e-mail address:
        username-yourdomainname
    Click Next.

7. In the Account Name field, enter an arbitrary name for this account.
    Use this name to distinguish this account from any others.
    Click Next.

8. The Account Wizard displays the settings that are entered. If any
    of the settings are incorrect, click Back to return to the previous steps.
    Click Finish.

    The new account now appears in the Mail & Newsgroups Account Settings
    window.

9. In the account list, select Outgoing Server (SMTP). The Outgoing Server
    (SMTP) Setting screen appears.
    In the Server Name field, enter the host-name of the SMTP server:
       mail.yourdomainname.com
    When configuring your POP3 logon, be sure to use the complete email address
    (username@yourdomainname.com). In order to send email using your email
    client, you MUST use SMTP authentication. When configuring your SMTP server
    information, enable SMTP authentication then enter your email account
    (username-yourdomainname) and your password. Passwords are case
    sensitive. View your email client help file for more information.
Note: SMTP authentication is not the same as SSL. Do not enable SAP or SSL
          in your configuration.

    Select User name and password.
    In the User Name field, enter the full username.
        username-yourdomainname
    Click OK.