Step Wise Manual Fast-mail mail settings for thunderbird
If you don't have a Fast-mail mail address. you can create an email id from here then you can Fast-mail email login.
Open Thunderbird Software App. Click on Email
When you click on the email, pop-up Set UP an Existing Account Screen.
Enter Your name, Fast-mail Email address and Password then press Continue.
Click on the Manual config menu at bottom.
Enter Below Fast-mail incoming server settings.
In incoming click on the dropdown menu and select IMAP.
Add server host :mail.messagingengine.com
Port: 993
select SSL/TLS
Enter Below Fast-mail outgoing server settings.
In outgoing select SMTP.
Add server host :mail.messagingengine.com
Port: 587
select SSL/TLS
Tap on Done. Now you are ready to use your Fast-mail email account on your Thunderbird.