Payer is not a sandbox demo customer

HTTP 422   payer_not_demo_customer

What it means

Sandbox only: simulate pay works only for requests sent to one of your business's demo customers.

What to do

Create the request for one of the demo customers you were given with your Sandbox business.

The response

HTTP/1.1 422
Content-Type: application/problem+json

{
  "type": "https://docs.txgold.money/errors/payer_not_demo_customer",
  "title": "Payer is not a sandbox demo customer",
  "status": 422,
  "code": "payer_not_demo_customer",
  "detail": "…",
  "requestId": "7219af94e39d"
}

Branch on code, never on title or detail: the code never changes once published, and the text may. Quote requestId to TxGold support. See all errors.