OPDC API error code

INVOICE_SET_TO_PAY

HTTP status 409

A payment names an invoice that a Sage user has staged for payment in Sage, so Sage's own next check run could pay it a second time. 409.

Clear the staged amount in Sage, then send the payment again. Nothing is written.

The API answers with a problem document (RFC 9457) whose type is https://twinn.engineering/errors/invoice-set-to-pay, and with X-Error-Code: INVOICE_SET_TO_PAY. Branch on the code, never on the detail text.

How errors work, and what to retry Every error code