Reason code

American Express reason code A02 is used when a transaction is processed without proper authorization. This typically means that the merchant either failed to obtain authorization, used an invalid or expired authorization code, or processed the transaction outside the time limit specified by Amex.

These disputes don’t necessarily mean the transaction was fraudulent—only that the technical authorization process wasn’t followed. Even if the cardholder participated in the transaction, the merchant can still be held liable if the required authorization was missing or invalid.

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If proper authorization was obtained, submit documentation proving compliance with Amex’s authorization rules:

• Provide the valid authorization approval code and timestamp
  
  
• Include terminal logs or gateway records confirming when and how authorization was secured
  
  

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Follow strict authorization procedures for every transaction to avoid these disputes:

• Always obtain a valid authorization code before completing a charge
  
  
• Make sure to process the transaction within Amex’s time limits to keep the approval valid