Step Wise Manual 21cn mail settings for thunderbird
If you don't have a 21cn mail address. you can create an email id from here then you can 21cn 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, 21cn Email address and Password then press Continue.
Click on the Manual config menu at bottom.
Enter Below 21cn incoming server settings.
In incoming click on the dropdown menu and select IMAP.
Add server host :pop.21cn.com
Port: 110
select SSL/TLS
Enter Below 21cn outgoing server settings.
In outgoing select SMTP.
Add server host :smtp.21cn.com
Port: 25
select SSL/TLS
Tap on Done. Now you are ready to use your 21cn email account on your Thunderbird.