Unable to pay for masterclass

I fill all data during the payment step. However I get this very informative popup


Nothing in form is highlighted red or in any way implied to be incorrect.

@Regule
I’m sorry you ran into this problem. This means the system could not validate your billing information.

From the look of things, this could be related to missing EEA VAT Number.

Could you please try again and share a full screenshot after closing the popup?

Thank you. That was the case.