在“新手指引——在线部署及预测——测试沙盒服务——第三步 点击【发送】检验返回结果”中报错："服务异常:Connect to studio-374:8016 [studio-374/172.18.16.245] failed: Connection refused (Connection refused)"。请问是什么原因？该如何解决？

报错代码如下：

{
    "logId": null,
    "errorCode": 500,
    "errorMsg": "服务异常:Connect to studio-374:8016 [studio-374/172.18.16.245] failed: Connection refused (Connection refused)",
    "timestamp": 0,
    "result": {}
}