Reason code

American Express reason code P01 is triggered when a transaction is submitted using a card number that is not assigned to an active or valid American Express account. This could be the result of a keying error, a test transaction gone wrong, or a fraud attempt using fabricated card data.

Because the card number doesn’t match any real Amex account, these charges are automatically declined or reversed. This type of dispute is not initiated by the cardholder but by Amex’s system validation process.

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If the transaction was submitted in error or as a test, acknowledge the issue and confirm no goods or services were delivered:

• Provide a statement confirming the transaction was not fulfilled or was voided
  
  
• Submit system logs or POS records showing the nature of the charge

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Prevent invalid charges by validating card numbers before processing:

• Use a payment gateway with built-in card number verification
  
  
• Never run test transactions using made-up or sample card data in a live environment

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