Step Wise Manual Pro mail settings for thunderbird
If you don't have a Pro mail address. you can create an email id from here then you can Pro 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, Pro Email address and Password then press Continue.
Click on the Manual config menu at bottom.
Enter Below Pro incoming server settings.
In incoming click on the dropdown menu and select IMAP.
Add server host :imap.poczta.onet.pl
Port: 993
select SSL/TLS
Enter Below Pro outgoing server settings.
In outgoing select SMTP.
Add server host :smtp.poczta.onet.pl
Port: 465
select SSL/TLS
Tap on Done. Now you are ready to use your Pro email account on your Thunderbird.