Subscribe form not working after migration

Hello,

I have this website which is developer version of website prepared for customer:

http://projekty.qcomputers.pl/PSFLP/#ebook
(ID directs to Mailpoet form)

It works great on this site.

Although after migration to live server which is:
http://lp2.psfund.pl/#ebook

The form submissions does not work. You can fill in the form but you will not receive email (i tested method with test email, it works) and there will be no person on adress list. As it never happened.

Can you help me? Any server settings?

https://ww.wp.xz.cn/plugins/wysija-newsletters/