Error while consuming API into .NET 3.5 with VS2008 into Console App

Question

Note:

 

The same code when I am execution on dotnetfiddle.net where framework version is v4.7. It is working perfectly. While the code I have written is compatible with v3.5

  

I am consuming an API into .NET 3.5 using Visual Studio 2008 using WebRequest. Following are the details of API:

 

Method:POST

ConetntType:application/x-www-form-urlencoded

With Three Parameters.

Key                                Value

ApiKey                           string

ApiOwner                       string

RequestBody                 json string

 

I am using the following code pattern.

WebRequest request = WebRequest.Create("https://hostname/RestWS/api/v1/order/orderPull");
                request.Method = "POST";
                string postData = "ApiOwner=sa&ApiKey=d564078......9530dec&RequestBody=";
                postData = postData + "{ \"orderNo\":\"o81075084\",\n \"statuses\":[],\n \"fromDate\":\"\",\n \"toDate\":\"\",\n \"pageNumber\":\"\",\n \"order_Location\":\"\",\n \"IsReplacementOrder\":\"\",\n \"orderSource\":\"\",\n  \"paymentType\":[\"Prepaid\",\"COD\"]\n }";
                byte[] byteArray = Encoding.UTF8.GetBytes(postData);
                request.ContentType = "application/x-www-form-urlencoded";
                request.ContentLength = byteArray.Length;
                Stream dataStream = request.GetRequestStream();  //Error at this line
                dataStream.Write(byteArray, 0, byteArray.Length);
                dataStream.Close();
                WebResponse response = request.GetResponse();
                Console.WriteLine(((HttpWebResponse)response).StatusDescription);
                dataStream = response.GetResponseStream();
                StreamReader reader = new StreamReader(dataStream);
                string responseFromServer = reader.ReadToEnd();
                Console.WriteLine(responseFromServer);
                reader.Close();
                dataStream.Close();
                response.Close();

Exception

 

Inner Exception:

Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.