Unfortunately, we cannot provide a simple answer to that. We have listed the most common problems for you:
1. Check the credit card details that you have entered again. It often happens that the long credit card number is entered incorrectly. An incorrect number causes the credit card company to reject your payment.
2. Check if your credit card has not expired. If this is the case then a payment is not possible. In that case, contact your bank or credit card company.
3. Check if your credit card limit has not been reached. If this is achieved then a payment is not possible at that time. In that case you have to wait a moment for the payment to fall within your limit.
4. When you make a payment abroad (a so-called cross-border payment), it can sometimes be blocked by the credit card company. In that case, please contact your bank or credit card company to make foreign payments possible.
5. Some credit cards have a limit for the maximum amount that can be included in one or more transactions. It is possible that if you make several payments within a few hours, the last payment will not go through.