Mastercard Payment Decline Code
Mastercard Decline Code 55: Invalid PIN
Category Authentication or PINRetry Guidance Conditional Decline (Editorial Classification)By Payment Defender Editorial TeamUpdated July 17, 2026Last reviewed July 17, 2026
What Mastercard Decline Code 55 Means
Mastercard decline code 55 (Invalid PIN) indicates that the PIN entered does not match the value the issuer has on record. It is returned during authorization to tell the merchant the payment could not be approved as submitted.
Where the Response May Come From
Mastercard code 55 (Invalid PIN) is returned by the card issuer during authorization and signals that the PIN entered did not match the issuer's records. Issuers rarely disclose the precise internal cause, so treat it as a directional signal rather than a full explanation.
Common Reasons for This Response
Common causes include a mistyped PIN, a forgotten PIN, or a PIN-pad entry error. The exact trigger depends on the issuer, the account, and how the transaction was submitted, so the same code can appear in several different situations.
Should the Merchant Retry the Payment?
Whether a retry helps depends entirely on the fact that the PIN entered did not match the issuer's records; retry only once that condition is genuinely resolved, and avoid immediate repeat attempts that conflict with network retry expectations.
Recommended Merchant Action
Confirm the cause first, since the PIN entered did not match the issuer's records, then ask the customer to re-enter the PIN carefully, and ask the customer to contact their issuing bank if the response points to their account.
What to Tell the Customer
Let the customer know the payment did not go through because the PIN entered did not match the issuer's records, and suggest re-entering their PIN or using another payment method. Keep the wording neutral and avoid asserting issuer details you cannot confirm.
How to Reduce Similar Payment Failures
Segmenting how often the PIN entered did not match the issuer's records appears by issuer and BIN, guiding careful PIN entry at the terminal, and submitting clean, correctly formatted authorization data can reduce avoidable occurrences of this decline over time.
Important Limitations
Decline-code meanings vary by processor, gateway, and payment environment, and issuers do not always disclose the specific reason behind a response. The retry classification on this page is Payment Defender editorial guidance, not an official Mastercard rule. Merchants should confirm handling with their processor or gateway.
Related Decline Codes
Sources and Review Information
- PayPal (Braintree): Braintree Processor Response Codes
- Mastercard: Mastercard Rules and Merchant Support
Last reviewed July 17, 2026
Raw network-response codes are supplemental to the complete processor or gateway response. Meanings and recommended actions can vary by issuer, processor, gateway, card network, payment method, region, and merchant configuration.