arcgis api for js gp服务返回的结果 500问题

     function completeCallback(jobInfo) {
                        // console.log(jobInfo);
                        var imageParams = new ImageParameters();
                        buffer.getResultImageLayer(jobInfo.jobId, null, null, function (gpLayer) {
                            console.log(gpLayer);
                            gpLayer.setOpacity(1);
                            map.addLayer(gpLayer);
                        });
                        // var layer = buffer.getResultImageLayer(jobInfo.jobId);
                        // console.log(layer);
                        // map.addLayer(layer);

                    }
Service buffer/MapServer not found