Depending on your bank and the credit card that you are using, you may have to confirm the first transaction with an additional token or a password, an amount of 0.00 EUR/USD may be displayed on the payments dialog.
This is normal, your credit card has to be pre-authorized and the correct amount will be debited in the next step.
If the process is successful the amount stated in the invoice will be charged in the next step.
Credit card confirmation screen