Subscription payment verification loop

Hi! I just installed Locus Maps 4 and I have tried getting the Silver subscription.
As I have been using Locus Maps Classic for along time, I was offered the 1y Silver free.
When I try to subscribe, I get a request to validate with my bank a payment of 0 (RON) which I approve and then the process repeats: again I am asked to subscribe, I get a request to validate with my bank, I approve, etc. This goes on and on.
I tried with 2 different banking systems: ING and Revolut, the result is the same.

I cannot subscribe to the Silver subscription and I have no other payment methods available in the app's UI (I live in Romania).