Unfortunately the error message is generated by the payment provider and we can't modify it. I agree that it would make sense for it to be more detailed alas it's out of our hands.
Sometimes you need to activate security features that are dependent on your card:
These are not active per default and you need to ask your bank to help you do this. This would lower the fraud rating and reduce the chance of the payment getting denied.
- Verified by VISA (for VISA)
- Mastercard Secure (for Mastercard)
Mastercard SecureCode is definitely enabled on my card. The issue lies somewhere else.
I just tried PayPal - the store doesn't even redirect me to the paypal page, only refreshes back to the first stage of checkout (billing information). No errors, no nothing. Just a refresh.
Attempted a different browser (Chrome instead on Firefox), but on it the store only shows prices in USD and keeps telling me I live in the United States. even though my account account clearly says I don't.
Yup, wasn't holding my breath. A pity, guess I'll have to wait for a Steam sale and pay Valve for being the middleman. And here I was looking forward to a nice weekend of EU4 with all the goodies enabled...