This is an ongoing issue. I've just tried it with three different cards (mastercard & visa) as well as PayPal and paysafecard with different addresses and amounts.When I click on the confirm button, I'm just put back on the "Get more gems"-page and this error pops up for almost a second:I've tried to follow these steps without success.Looks like their gateway to the payment service provider DigitalRiver is regularly broken and only fixed some hours later.