This tutorial will show you how to configure a new account for POP access (rather than IMAP).
1. Select ToolsEdit > Account Settings > Account Actions > Add Mail Account…
2. Enter your full name, username (check with your email provider; it is your full email address) and password and click Continue.
3. Thunderbird will attempt to configure your account settings automatically using IMAP. While the attempt is in progress, click Manual config.
4. Enter or modify your account details as follows:
5. Once these settings have been changed, click Re-test. You should get a message that says that a configuration was found at the email provider. If not, check your settings and test again.
6. Click on Done to exit the Mail Account Setup dialog. View the Account Settings page and you will see that your new account has been created. Also check if our Outgoing Server (SMTP) is correct for this account (at the bottom of the screenshot).
7. Check that your incoming and outgoing mail is working correctly. If everything is working as it should (which means you can send and receive email and see your old emails; note that some email providers may not give you access to all of your emails or all your email folders; check with your email provider) and you accidentally created an IMAP account earlier, then delete the accidentally created IMAP account as follows: open ToolsEdit > Account Settings, select the accidentally created IMAP account with the IMAP server setting, then select Account Actions > Remove Account from the drop-down list underneath the account list on the left.
For more information about account connection information, see Manual Account Configuration.