WebSocket and WebGL error

Hi there, I'm trying to use this free websocket pack with Unity. The demo works ok.

But now I need to do something more real. I'm trying to built a Server C# (console app) to run on Windows and make the Unity WebGL client to connect to it. My server code follows this example.

Server code:

 class Program
 {
     public static void Main(string[] args)
     {
         TcpListener server = new TcpListener(IPAddress.Parse("127.0.0.1"), 8080);
         server.Start();
         Console.WriteLine("Server is running 127.0.0.1:8080");
 
         TcpClient client = server.AcceptTcpClient();
         Console.WriteLine("Client accepted");
         NetworkStream stream = client.GetStream();
 
         //loop to handle the stream
         while (true)
         {
             while (!stream.DataAvailable) { };

             Byte[] bytes = new Byte[client.Available];
             stream.Read(bytes, 0, bytes.Length);
             Console.WriteLine("Data> " + Encoding.UTF8.GetString(bytes));
             var data = Encoding.UTF8.GetString(bytes);
 
              if (new Regex("^GET").IsMatch(data))
             {
                 Console.WriteLine("GET");
 
                 SHA1 sha1 = SHA1.Create();
                 Byte[] response = Encoding.UTF8.GetBytes(
                     "HTTP/1.1 101 Switching Protocols" + Environment.NewLine +
                     "Upgrade: websocket" + Environment.NewLine +
                     "Connection: Upgrade" + Environment.NewLine +
                     "Sec-WebSocket-Accept" + Convert.ToBase64String(
                         sha1.ComputeHash(
                             Encoding.UTF8.GetBytes(
                                 new Regex("Sec-WebSocket-Key: (.*)").Match(data).Groups[1].Value.Trim() +
                                 "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
                                 )
                         )
                     ) + Environment.NewLine + Environment.NewLine);
             }
             else
                 Console.WriteLine("!GET");
         }
     }
 }

And here is the client code:

 public class EchoTest : MonoBehaviour
 {    
     IEnumerator Start()
     {
         WebSocket w = new WebSocket(new Uri("ws://localhost:8080"));
         yield return StartCoroutine(w.Connect());
 
         w.SendString("Hi there");
         int i = 0;
         while (true)
         {
             string reply = w.RecvString();
             if (reply != null)
             {
                 Debug.Log("Received: " + reply);
                 t.text = reply;
                 w.SendString("Hi there" + i++);
             }
             if (w.error != null)
             {
                 Debug.LogError("Error: " + w.error);
                 w.Close();
 
                 yield return StartCoroutine(w.Connect());
                 break;
             }
             yield return 0;
         }
         w.Close();
     }
 }

When I run the server and unity, the server actually print the line "GET" on console, but nothing happens after. The unity then print the error message on block "if (w.error != null)":

Error: The WebSocket connection has already been closed. UnityEngine.Debug:LogError(Object) c__Iterator0:MoveNext() (at Assets/Example/EchoTest.cs:28)

How can I exchange messages between then? What am I doing wrong or missing?

Thanks.