Amex Reason Code A02: No Valid Authorization

What Amex reason code A02 means

A02 is the American Express code for a charge with no valid authorization behind it. Every charge needs an approval from Amex before you submit it. A02 means Amex’s records show one of the following:

• No authorization was requested for the charge.
• An authorization was requested and declined, and the charge was submitted anyway.
• The approval that exists doesn’t match the submitted charge (different card number, amount or merchant).

Like other Authorization codes, A02 is a processing-rules dispute rather than a Card Member complaint about the purchase itself.

Common causes

• “Forced” sales: entering a voice or manual approval code that wasn’t actually issued for that charge
• Offline or store-and-forward transactions submitted after a decline
• Subscription retry logic that settles a charge on a failed authorization
• Gateway or platform migrations where stored-card charges weren’t re-authorized correctly
• Approval codes reused from an earlier transaction

Evidence that wins an A02 dispute

1. Authorization log from your gateway or processor: approval code, date, time, amount and card number (masked) for this charge.
2. Settlement record showing the submitted charge used that approval.
3. Proof the details match: same card, same amount (or within an allowed tolerance), same merchant ID.
4. For voice authorizations: the approval code and call record from the authorization center.

If the log shows a decline, there is no rebuttal to make. Accept and fix the flow.

How A02 differs from other authorization codes

Knowing which one you have tells you what record to pull: A02 lives or dies on whether an approval code exists for this exact charge.

How to prevent A02 disputes

• Never submit a charge after a decline; ask the customer for another payment method.
• Disable or tightly control manual “force” entry in your terminal or gateway.
• Make sure subscription retry logic only settles charges with an approval.
• After any payment migration, test that stored cards are authorized before capture.

Should you fight or accept?

Fight when you have an approval code that matches the charge. These are often clean wins because the evidence is a single record.

Accept when there’s no approval or the approval was a decline. A02 is a rules violation, and arguing that the customer received the goods won’t change the outcome.