application/problem+json media type. Each error carries a JDC-NNNN code in the code field. Match on the code, not on the text.
The SOAP interface and the Pix address do not carry JDC-NNNN codes. On those surfaces, JD and the engines receive the answers that How routing works describes.
type– A URI that identifies the error code.title– The text of the HTTP status.status– The HTTP status code.detail– The explanation for this occurrence of the error.code– A stable identifier for the error (JDC-NNNN). Use it for programmatic handling and support requests.errors– Optional. A list of field errors, each with alocationand amessage.instance– Optional. The identifier of this occurrence.
JD Courier errors
400
401
403
404
409
413
422
500
503
Other 4xx
Boot refusal
This code does not appear in an HTTP answer. The process writes it to its log and stops at boot.

