Form doesn't appear

Hi!

I have problem with reservation. When I try to book some places at the schema the form with contact details doesn’t appear.

Table summary is displayed correctly, but below of Checkout button following inscription is still, despite the marked places.

Please add to your cart at least one place.
Sorry, you can not add this place to your cart!

http://dobragrupa.pl/14V1-ANP/rezerwacja1/

Please help.

https://ww.wp.xz.cn/plugins/book-a-place/