.NET 4.x Не работает прокси сервер - C#

public static void HttpProxyActivity()
        {
 
            int localProxyPort = 17325;
            HttpListener lproxy_s = new HttpListener();
            lproxy_s.Prefixes.Add(string.Format("http://*:{0}/", localProxyPort));
            ServicePointManager.DefaultConnectionLimit = 1000;
            lproxy_s.Start();

            try
            {
                while (true)
                {
                    Thread.Sleep(0);
                    Console.WriteLine("Listening...");
                    var context = lproxy_s.GetContext();
                    var requestString = context.Request.RawUrl;
                    Console.WriteLine("Got request for " + requestString);
 
                    //requested site is not denied
                    if (!requestString.Contains(Dns.GetHostEntry("tut.by").AddressList[0].ToString()) && !requestString.Contains("tut"))
                    {
 
                        try
                        {
 
                            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(requestString);
                            request.AllowAutoRedirect = false;
                            request.KeepAlive = context.Request.KeepAlive;
                            request.Proxy.Credentials = CredentialCache.DefaultCredentials;
                            request.Method = context.Request.HttpMethod;
                            request.ContentType = context.Request.ContentType;
 
                            var cookies = new CookieContainer();
                            cookies.Add(new Uri(requestString), context.Request.Cookies);
                            request.CookieContainer = cookies;
                            request.Timeout = 20000;
 
                            HttpWebResponse resp;
 
                                try
                                {
                                    resp = (HttpWebResponse)request.GetResponse();
                                }
                                catch (WebException err)
                                {
                                    resp = (HttpWebResponse)err.Response;
                                }
 
                            Stream stream = resp.GetResponseStream();
                            StreamReader sr_ = new StreamReader(stream, Encoding.GetEncoding(resp.CharacterSet));
 
                            string response_from_remote_server = sr_.ReadToEnd();
 
                            var rs = new RequestData(request, context);
                            if (request.Method != "GET")
                            {
                                var t = resp.GetResponseStream();
                                HttpListenerResponse response = context.Response;
                                response.ContentType = resp.ContentType;
                                byte[] buf = new byte[2048];
                                buf = System.Text.Encoding.UTF8.GetBytes(response_from_remote_server);
                                response.ContentLength64 = buf.Length;
                                using (Stream output = response.OutputStream)
                                {
                                    output.Write(buf, 0, buf.Length);
                                }

                            }
                            else
                            {
                                var t = resp.GetResponseStream();
                                HttpListenerResponse response = context.Response;
                                response.ContentType = resp.ContentType;
                                byte[] buf = new byte[2048];
                                StreamReader sr = new StreamReader(t);
                                string l = sr.ReadToEnd();
                                response.ContentLength64 = l.Length;
                                using (Stream output = response.OutputStream)
                                {
                                    output.Write(System.Text.Encoding.UTF8.GetBytes(l), 0, l.Length);
                                }
                                sr.Close();

                            }
                        }
                        catch (Exception ex)
                        {
                            Console.WriteLine(ex.Message);
                        }
                    }
                    else
                    {
                        try
                        {
 
                            var request = WebRequest.Create(requestString) as HttpWebRequest;
                            request.AllowAutoRedirect = false;
                            request.KeepAlive = context.Request.KeepAlive;
                            request.Proxy.Credentials = CredentialCache.DefaultCredentials;
                            request.Method = context.Request.HttpMethod;
                            request.ContentType = context.Request.ContentType;
 
                            var cookies = new CookieContainer();
                            cookies.Add(new Uri(requestString), context.Request.Cookies);
                            request.CookieContainer = cookies;
                            request.Timeout = 20000;
 
                            var rs = new RequestData(request, context);
                            if (request.Method != "GET")
                            {

                                HttpListenerResponse response = context.Response;
                                string responseString = "<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"><html><head><title>404 Not Found</title></head><body><h1>Not Found</h1><p>The requested URL /404 was not found on this server.</p></body></html>";
                                response.ContentType = "text/html; charset=UTF-8";
                                byte[] buffer = Encoding.UTF8.GetBytes(responseString);
                                response.ContentLength64 = buffer.Length;
                                using (Stream output = response.OutputStream)
                                {
                                    output.Write(buffer, 0, buffer.Length);
                                }

                            }
                            else
                            {
                                IAsyncResult result = (IAsyncResult)request.BeginGetResponse(
                                new AsyncCallback(RespCallback), rs);
                                HttpListenerResponse response = context.Response;
                                string responseString = "<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"><html><head><title>404 Not Found</title></head><body><h1>Not Found</h1><p>The requested URL /404 was not found on this server.</p></body></html>";
                                response.ContentType = "text/html; charset=UTF-8";
                                byte[] buffer = Encoding.UTF8.GetBytes(responseString);
                                response.ContentLength64 = buffer.Length;
                                using (Stream output = response.OutputStream)
                                {
                                    output.Write(buffer, 0, buffer.Length);
                                }

                            }
                        }
                        catch (Exception ex)
                        {
                            Console.WriteLine(ex.Message);
                        }
 
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
 
        }