Reference pagesReason codes
Processing error
American Express P01: Unassigned Card Account
An 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 the app handles it
Arrives in the app as: General
How long you have to respond
- Merchant response
- 20 days from the inquiry or chargeback notice
Where this comes from
- American Express, Merchant Regulations International, 17 April 2026
- Stripe, reason code categories Accessed 8 September 2026.
Other American Express processing error codes
Do The Proof drafts dispute responses for Shopify stores.
You pay when a dispute is won. Not before.