Optional ReadonlydetailServer-provided error detail, when the body carried one.
Optional ReadonlyerrorRFC 6749 error code, e.g. 'invalid_grant' or 'invalid_request'.
ReadonlystatusHTTP status code; 0 when the request never produced a response.
ReadonlyurlRequest URL with any query string, for diagnostics.
OAuth2 token endpoint failure (RFC 6749 error responses).