Processing Errors
M04 Merchant Accepted
Details
American Express reason code M04 is used when a merchant accepts a transaction that was previously declined by the issuer. This typically happens when a transaction is retried after a decline, and the merchant mistakenly processes the charge without obtaining a valid authorization approval.
Even if the cardholder received the goods or services, the merchant may still be held liable because the transaction lacked a proper authorization. These disputes often result from POS system errors, misunderstanding of decline codes, or manual reattempts without reauthorization.
Timing to raise the dispute (Issuer/Cardholder)
Timing to respond to the dispute (Acquirer/Merchant)
How to respond?
If a valid authorization was obtained, provide documentation to show the transaction was approved:
-
Submit the authorization code, timestamp, and terminal or gateway logs
-
Include any notes or correspondence explaining how the transaction was reattempted correctly
How to prevent?
Handle declined transactions carefully to avoid unintentional acceptance:
-
Never retry a declined card without obtaining a new authorization approval
-
Train staff to recognize issuer decline codes and follow proper reattempt procedures