C＃请求后状态400错误请求

Question

我目前正在开发一个C＃程序，该程序应该从我托管的REST API中获取数据。

API要求从POST请求返回的身份验证令牌。

当我尝试使用C＃进行POST时，收到一个错误的请求（状态400），但GET请求工作正常。现在，我的问题是我做错了什么，或者可能是导致该错误的原因。与邮递员进行请求时，两者都可以正常工作。

POST功能：

void POST(string url, string jsonContent) {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.Method = "POST";

        System.Text.UTF8Encoding encoding = new System.Text.UTF8Encoding();
        Byte[] byteArray = encoding.GetBytes(jsonContent);

        request.ContentLength = byteArray.Length;
        request.ContentType = @"application/json";

        using (Stream dataStream = request.GetRequestStream()) {
            dataStream.Write(byteArray, 0, byteArray.Length);
        }
        long length = 0;
        try {
            using (HttpWebResponse response = (HttpWebResponse)request.GetResponse()) {
                length = response.ContentLength;
                Console.WriteLine(response);
            }
        } catch (WebException ex) {
            Console.WriteLine(ex);
        }
    }

GET函数：

string GET(string url) {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        try {
            WebResponse response = request.GetResponse();
            using (Stream responseStream = response.GetResponseStream()) {
                StreamReader reader = new StreamReader(responseStream, System.Text.Encoding.UTF8);
                return reader.ReadToEnd();
            }
        } catch (WebException ex) {
            WebResponse errorResponse = ex.Response;
            using (Stream responseStream = errorResponse.GetResponseStream()) {
                StreamReader reader = new StreamReader(responseStream, System.Text.Encoding.GetEncoding("utf-8"));
                String errorText = reader.ReadToEnd();
                // log errorText
            }
            throw;
        }
    }