Adyen saysHard decline
8Invalid Card Number
What it means
Invalid card number
The card number does not exist or is not valid for this issuer.
What to do
Ask the shopper to re-enter the number or use another card. Do not retry the same number.
Don't retry as-isWho can fix it: The shopper
Yuno response codeINVALID_CARD_NUMBER
Source:Adyen docs — Refusal reasons
Reference only. Codes and descriptions come from each provider's public documentation. The Yuno response code is a reference mapping and does not guarantee how a specific transaction is processed.