A transaction can be blocked either by the bank, or by the risk profile of the merchant.
The most frequent reason is that Adyen receives a negative response by the bank. This can have multiple causes: the card number or CVC is incorrect, the amount exceeds your limit, foreign currencies are not accepted on your card, etc. Please make sure all details are filled in correctly. If the problem persists, contact your issuing bank for the specific reason.
Merchants set up risk profile to avoid fraud. Your transaction may be flagged as fraud by this safety mechanism. If the transaction is marked incorrectly as fraud, please contact the merchant directly. If the merchant requires assistance to resolve this issue, they can contact us.