Root Cause

• Incorrect card number entry: The card or account number entered by the customer is mistyped or incomplete.

• Invalid card format: The card number does not conform to standard formats (e.g., missing digits, invalid Luhn check).

• Outdated stored card details: The payment attempt was made using an expired or invalid saved card.

• Card no longer active: The card has been deactivated or replaced by the issuer.

Troubleshooting and Solutions

• Inform the customer that their transaction failed due to an invalid card number.

• Ask the customer to:

  • Carefully review and re-enter their card or account number.

  • Try a different card or payment method if the issue persists.

• Internally:

  • Ensure that saved card data is up to date and formatted correctly.