i can not telnet in c#.un sucssessful send and recive .help please

static void Main(string[] args)
        {


            try
            {
                NetworkStream stream;
                Byte[] data;
                while (true)
                {
                    // Create a TcpClient.
                    // Note, for this client to work you need to have a TcpServer 
                    // connected to the same address as specified by the server, port
                    // combination.
                   
                    TcpClient client = new TcpClient("cu-ekhtiari", 23);

                    stream = client.GetStream();

                    data = new Byte[256];

                    // String to store the response ASCII representation.
                    String responseData = String.Empty;

                    // Read the first batch of the TcpServer response bytes.
                    Int32 bytes = stream.Read(data, 0, data.Length);
                    responseData = System.Text.Encoding.ASCII.GetString(data, 0, bytes);
                    Console.WriteLine("Received: {0}", responseData);





                    string message = Console.ReadLine();
                    // Translate the passed message into ASCII and store it as a Byte array.
                    data = System.Text.Encoding.ASCII.GetBytes(message);

                    // Get a client stream for reading and writing.
                    //  Stream stream = client.GetStream();

                    

                    // Send the message to the connected TcpServer. 
                    stream.Write(data, 0, data.Length);

                    Console.WriteLine("Sent: {0}", message);

                    // Receive the TcpServer.response.

                    // Buffer to store the response bytes.
                    data = new Byte[256];

                    // String to store the response ASCII representation.
                     responseData = String.Empty;

                    // Read the first batch of the TcpServer response bytes.
                     bytes = stream.Read(data, 0, data.Length);
                    responseData = System.Text.Encoding.ASCII.GetString(data, 0, bytes);
                    Console.WriteLine("Received: {0}", responseData);
                    
                }
                // Close everything.
               // client.Close();
            }
            catch (ArgumentNullException e)
            {
                Console.WriteLine("ArgumentNullException: {0}", e);
            }
            catch (SocketException e)
            {
                Console.WriteLine("SocketException: {0}", e);
            }

            Console.WriteLine("\n Press Enter to continue...");
            Console.Read();
        }
    }
}