Errors & troubleshooting
Use the response body and HTTP status together.
Client errors
400 indicates an invalid field or operation, including insufficient signing credits. Framework validation errors can contain statusCode, code, error, and message. Application errors usually include error, and some PDF preparation failures also include errorCode. 401 means unauthorized, 403 forbidden, and 404 a resource that is missing or unavailable to the caller.
Conflicts and service failures
409 can indicate that stored document contents changed unexpectedly. A 500 indicates a processing failure; deletion can return 502 if the stored file could not be removed. Do not blindly repeat creation or signing requests after a timeout: the operation may already have succeeded. Retrieve the document and reconcile state first.
Browser network errors
A network error may reflect connectivity, a blocked redirect, or CORS configuration. It does not prove that the API did not process the request. The console omits cookies, does not follow redirects, and never automatically retries a mutation. Cancellation stops waiting in the browser, not work already started on the server.