Authorization
A02 No Valid Authorization
Details
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.
Timing to raise the dispute (Issuer/Cardholder)
Timing to respond to the dispute (Acquirer/Merchant)
How to respond?
If proper authorization was obtained, submit documentation proving compliance with Amex’s authorization rules:
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Provide the valid authorization approval code and timestamp
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Include terminal logs or gateway records confirming when and how authorization was secured
How to prevent?
Follow strict authorization procedures for every transaction to avoid these disputes:
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Always obtain a valid authorization code before completing a charge
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Make sure to process the transaction within Amex’s time limits to keep the approval valid