Launch Mozilla Thunderbird.
Click Create a new account. The Account Wizard starts.
Click Email account and press Next >. Fill out the form that appears: In the Your Name field, type in your name that will be shown to your e-mail recipients.
In the Email Address field, type in firstname.lastname@example.org.
Click Next > to continue the Wizard. Provide the following information about your incoming server: Select the POP type.
Type in mail.yourdomainname.com in the Incoming Server field.
Click Next > to proceed to the next step of the Wizard. The User Names Wizard step is displayed. Type in email@example.com in the Incoming User Name field.
Click Next > to continue. The Account Name Wizard step is displayed. Type in the reference name for your account, for example “Work Account” in the Account Name field.
Click Next > to proceed to the final Wizard step. The summary information is displayed. Check if everything is correct.
Click Finish to complete the Wizard. Your POP3 email account is now created.
On the Thunderbird menu, select Tools > Account Settings. The Account Settings dialog window is displayed.
In the folder list, select the just created account and click Server Settings. The incoming server settings for your account are displayed at the right part of the Account Settings window.
Under Security Settings select NONE/NO. ( You can use the SSL option if you have the service)
In the folder list of the Account Setting window, click Outgoing Server (SMTP). The Outgoing Server (SMTP) Settings are displayed at the right part of the window. Here you can see all SMTP servers set up on your computer (if there any).
Click Add. The SMTP Server dialog box is displayed. Fill out the form as follows: In the Description field (optional), type in a free-form description of your outgoing mail server.
In the Server Name field, type mail.yourdomainname.com
Select the Use name and password checkbox and enter firstname.lastname@example.org in the User Name field.
Under Use secure connection select NONE/NO.
Click OK to save changes and exit the SMTP Server dialog box.
Select your account (‘Work Account’) in the folder list of the Account Settings window. The account settings are displayed at the right part of the window.
From the Outgoing Server (SMTP) drop-down list, select the just added SMTP server.
Click OK to save your changes and exit the Account Settings dialog window. You have just configured your POP3 email account.
On the Thunderbird main window, click on the down-oriented triangle to the right of the Get Mail icon. The drop-down list opens that contains your existing e-mail accounts.
Select the just configured account. You are prompted to enter the password
Type in your password and select the Use Password Manager to remember this password checkbox if necessary.
Usually, the port used for the Outgoing Mail Server/SMTP Service is 25. However, there might be a situation where your ISP might be blocking the use of port 25 for SMTP service. Many ISPs block port 25 in order to minimize the amount of spam sent using their network. If you are facing issues sending mails using the default port 25, you can confirm with your ISP whether port 25 is indeed blocked by them.
To circumvent this, Sibername allows you to use an alternate port 26 for sending mails if port 25 is blocked: