通过WebRequest的NetworkCredential身份验证不起作用

Question

我在API中进行了调用，但无法通过用户名和密码进行身份验证，并且可以通过应用程序进行身份验证，但在C＃中无法。我在下面使用WebRequest代码

    private string Create (MontaChangeDice )
    {

        string user = "integration";
        string password = "xxxTestxxx";
        NetworkCredential cred = new NetworkCredential(user, password);
        WebRequest request = WebRequest.Create("https://CallURL");
        request.Credentials = cred;
        request.Method = "POST";
        string postData = new JavaScriptSerializer().Serialize(Dice);
        byte[] byteArray = Encoding.UTF8.GetBytes(postData);
        request.ContentType = "application/json";
        request.ContentLength = byteArray.Length;

        Stream dataStream = request.GetRequestStream();
        dataStream.Write(byteArray, 0, byteArray.Length);

        }

ps：发布的用户和网址仅是示例