Reference pagesReason codes
Processing error
American Express P01: Unassigned Card Account
A American Express dispute reason code, what it asks you to prove, and what Do The Proof puts in the response.
What this code means
Card number not assigned
What the network says wins it
Clearing Record from the terminal that electronically read the Card Account
- Authorization and processing records
How Do The Proof handles it
Arrives in Do The Proof as: General
How long you have to respond
- Merchant response
- 20 days from the inquiry or chargeback notice
There is no pre-arbitration. American Express is both the issuer and the network, and rules after one merchant response; it may then issue a final chargeback.
Merchants in the FR2, FR4 and FR6 programmes get no inquiry at all.
Where this comes from
- American Express, Merchant Regulations International, 17 April 2026 Read 2026-09-08.
- Stripe, reason code categories Read 2026-09-08.
Other American Express processing error codes
Do The Proof drafts dispute responses for Shopify stores. Connect store