Proxy Not connected error

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C#

Dear all
i am using internet explorer with program "analog proxy" to use proxy while connecting to the internet
this is the steps i made:
tools->internet options->connections-> Lan settings-> and i checked use proxy server for Lan..... with address: 192.168.1.240 and port:6588
i tried to connect to the internet through c# but always i get "NOT CONNECTED" message.. which means that i can not connect to internet
can anyone help me to connect to net through my proxy???
here it is my code

if (WebRequest.DefaultWebProxy.GetProxy(new System.Uri("https://www.o-survey.com/")).ToString() == "https://www.o-survey.com/")
          {
              // A proxy is not in use here
              MessageBox.Show("A proxy is not in use here");
          }
          else
          {
            MessageBox.Show("A proxy is in use");
              // A proxy is in use
          }
          const int PORT = 6588;
          IPAddress IP;
          IPAddress.TryParse("192.168.1.240", out IP);
          // This constructor arbitrarily assigns the local port number.
          UdpClient udpClient = new UdpClient(PORT);
          Socket receiveSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
          try
          {
              udpClient.Connect("192.168.1.240", PORT);
              if (udpClient.Client.Connected)
              // Sends a message to the host to which you have connected.
              Byte[] sendBytes = Encoding.ASCII.GetBytes("CONNECT");
              udpClient.Send(sendBytes, sendBytes.Length);
              //IPEndPoint object will allow us to read datagrams sent from any source.
              IPEndPoint RemoteIpEndPoint = new IPEndPoint(IP, PORT);
              // Blocks until a message returns on this socket from a remote host.
              Byte[] receiveBytes = udpClient.Receive(ref RemoteIpEndPoint);
              string returnData = Encoding.ASCII.GetString(receiveBytes);
              // Uses the IPEndPoint object to determine which of these two hosts responded.
              MessageBox.Show("This is the message you received " + returnData.ToString());
              MessageBox.Show("This message was sent from " + RemoteIpEndPoint.Address.ToString() + " on their port number " + RemoteIpEndPoint.Port.ToString());
              System.Uri Url = new System.Uri("https://www.o-survey.com/");
              System.Net.WebRequest WebReq;
              System.Net.WebResponse Resp;
              WebReq = System.Net.WebRequest.Create(Url);
              try
              {
                  Resp = WebReq.GetResponse();
                  Resp.Close();
                  WebReq = null;
                  MessageBox.Show("connected");
              }
              catch
              {
                  WebReq = null;
                  MessageBox.Show("not connected");
              }
              udpClient.Close();
          }
          catch (Exception e)
          {
               MessageBox.Show(e.ToString());
          }