Debit card Authentication doesn’t work – Registration and payment fails

Hello, dear team

I have the simple membership plug in in my sete: minimalism.bg. At the start of the payment process, after the user fill their name, email, card data and hit register – it shows one white window for authentication of the payment. Some debit/credit cards has additional codes for authentication of the payment. So, in that small window should be written what the user should do in order to verify the payment – go to app to verrify it, put some code or something else. But in this case – the window stays just white with no information (screenshot here: https://minimalism.bg/wp-content/uploads/2020/09/Screenshot-2020-09-27-at-15.52.27.png). So, the user can not proceed with the payment and the registration faild.

Can you please tell me if you or I can fix this somehow, because besicaly the whole registration and payment fails that way?

Thank you very much,
Veneta

The page I need help with: [log in to see the link]