This would appear to be an external banking payment error connected to the type of card you are using, and if the card and or account connected to it is authorized for international transactions.
We occasionally see this error and more so with Pre-Paid type cards from 3rd party issuers. We have found that the card holder needs to contact their card issuing bank and have it approved for International transactions.
We advise that you contact your bank and have the card approved for International transactions.
If they require our company particulars they are;
Royal Golden Enterprise GmbH trading as Swiss Gold Global
Leutschenbachstrasse 95, 8050 Zurich. Switzerland.
If your card is registered in PayPal or Payza you could try selecting alternative payment type.