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Mastercard

Mastercard Issuer Response Code 55: Invalid PIN

hard decline

Last updated: October 8, 2026

Key details

Brand
Mastercard
Code
55
Response
55
Detailed Response
Invalid PIN
hard decline
This transaction is not retriable

Payments failing with code 55 are hard declines and typically cannot be recovered by retrying. SmartRetry still helps you avoid future hard declines with smarter routing and validation.

But many other declines in your payment flow may still be recoverable. SmartRetry identifies which failed transactions have recovery potential and applies the right strategy to recover them.

Find out what you can recover >

What it means

Mastercard issuer response code 55 indicates that the transaction was declined because the customer entered an incorrect Personal Identification Number (PIN). The issuing bank successfully reached the account but blocked the transaction due to the PIN mismatch. It serves as a prompt for the cardholder to correct their entry before they exceed the issuer's allowed attempt limit.

Why does code 55 occur?

  • The cardholder accidentally mistyped their PIN on the terminal or point-of-sale device.
  • The customer has forgotten their correct PIN and guessed incorrectly during checkout.
  • A merchant integration or hardware defect incorrectly passed malformed or encrypted PIN block data to the issuer.

How to solve 55?

For attended point-of-sale transactions, prompt the customer to re-enter their PIN carefully. If they cannot remember the correct PIN, advise them to use an alternative payment method and contact their issuing bank. For card-not-present or recurring online transactions where you cannot collect a PIN, do not attempt automated retries; instead, contact the customer to update their payment details.

Solving as a merchant

Halt automated retries immediately to prevent triggering a hard block for exceeded PIN attempts (such as code 75). Ensure your POS or terminal software clearly displays a 'Wrong PIN' message to the shopper, allowing them a chance to try again safely. If the transaction channel does not support PIN entry, flag the failure and prompt the user for a new payment method.

Solving as a client

Carefully re-enter your PIN on the terminal pad. If you have forgotten your PIN, use a different credit or debit card to complete the purchase, and contact your issuing bank to request a PIN reset.

Tip from SmartRetry Suppress automated retries immediately to avoid triggering issuer PIN lockouts on the customer's card. If processing online debit, evaluate whether your gateway supports routing transactions through PINless rails rather than resubmitting the same credential payload.

See the full list of Mastercard's decline codes >Find code on Mastercard's website >

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Kyle Regacho

Author

Kyle Regacho
LinkedInFind me on Linkedin

Focused on payment recovery, decline codes, and authorization optimization at SmartRetry. Helps payment teams turn failed transactions into recovered revenue

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Decline codes tell you why. We fix it.

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