Когда Socket.Send call => Существующее соединение было принудительно закрыто удаленным хостом.

Question

У нас есть ServerPC и более ClientPC, эта система о сервере / клиенте CafeGame / GameNet.

Моя проблема: когда сервер подключен к сети И после этого клиенты подключены, все в порядке!Но когда клиент подключен к сети, и после этого сервер подключен. У нас проблема.

Существующее соединение было принудительно закрыто удаленным хостом

Код сервера

   {
   public Dictionary<string, ClientData> lstClients = new Dictionary<string, ClientData>();
   private delegate void CommandReceivedEventHandler(DataPacket.DataPacket data, ClientData sender);
   private event CommandReceivedEventHandler CommandReceived;

        private void AcceptSocket(IAsyncResult ar)
        {

        TcpListener listener = (TcpListener)ar.AsyncState;
        try
        {
            ClientData clientData = new ClientData(listener.EndAcceptSocket(ar));

            int i = clientData.Socket.RemoteEndPoint.ToString().IndexOf(':');
            string IPAddress = clientData.Socket.RemoteEndPoint.ToString().Substring(0, i);


            clientData.IsConnected = true;

            if (lstClients.ContainsKey(IPAddress))
            {
                lstClients.Remove(IPAddress);
                lstClients.Add(IPAddress, clientData);
                dicClientUserControl[IPAddress].clientData = null;
                dicClientUserControl[IPAddress].clientData = clientData;
                dicClientUserControl[IPAddress].clientData.IsConnected = true;
            }
            else
            {
                Dispatcher.Invoke((Action)(() =>{u = new PCu(clientData, this, 0);}));
                clientData.IsOnline = false;
                dicClientUserControl.Add(IPAddress, u);
                lstClients.Add(IPAddress, clientData);
                Dispatcher.Invoke((Action)(() => { WarpPanelClient.Children.Add(u); }));
            }

            clientData.Socket.BeginReceive(clientData.ReceiveBuffer, 0, clientData.ReceiveBuffer.Length, SocketFlags.None, new AsyncCallback(Receive), clientData);
            listener.BeginAcceptSocket(AcceptSocket, listener);
        }
        catch (Exception ex)
        {
            listener.BeginAcceptSocket(AcceptSocket, listener);
        }
    }
    private void Receive(IAsyncResult ar)
    {
        ClientData clientData = (ClientData)ar.AsyncState;
        SocketError err;
        int byteReceived = clientData.Socket.EndReceive(ar, out err);


        if (err != SocketError.Success)
        {
            byteReceived = 0;
            clientData.IsConnected = false;
            clientData.IsOnline = false;
        }

        clientData.IsConnected = true;
        DataPacket.DataPacket data = DataPacket.DataPacket.FromByte(clientData.ReceiveBuffer);
        CommandReceived.Invoke(data, clientData);

        try
        {
            clientData.Socket.BeginReceive(clientData.ReceiveBuffer, 0, clientData.ReceiveBuffer.Length, SocketFlags.None, new AsyncCallback(Receive), clientData);
        }
        catch (SocketException ex)
        {
            clientData.IsConnected = false;
            clientData.IsOnline = false;
            lstClients[clientData.AddressText] = clientData;
            //dicClientUserControl[clientData.AddressText] = u;
        }
        catch (Exception ex)
        {

        }
    }
    private bool SendCMD(DataPacket.DataPacket data)
    {

        try
        {
            else if (clientData.IsConnected)
                clientData.Socket.Send(data.ToBytes());//?? Crash 
            return (true);
        }
        catch (Exception ex)
        {
            //An existing connection was forcibly closed by the remote host
            IS_CONNECTED(false);
            return false; 
        }
    }
}

Класс на сервере

    public class ClientData
    {
    public byte[] ReceiveBuffer = new byte[10240];
    DataPacket.DataPacket Data = new DataPacket.DataPacket();
    bool isConnected;// Connected Or Not
    bool isOnline = false;// Loged in Or Not
    public Socket Socket { get; private set; }
    public string NameClient { get; set; }
    public int Ver { get; set; }
    public int id { get; set; }
    public string Username { get; set; }
    public string Password { get; set; }

    public ClientData(Socket socket)
    {
        this.Socket = socket;
        int i = Socket.RemoteEndPoint.ToString().IndexOf(':');
        AddressText = Socket.RemoteEndPoint.ToString().Substring(0, i);
    }
}

Код клиента

    bool isConnected;
    public bool Connect(IPAddress IP, int Port, string SystemName)
    {
        try
        {

            if (isConnected == false)
            {

                SocketClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                SocketClient.Connect(IP, Port);
                isConnected = true;
                return true;
            }

            else
                return true;
        }
        catch (Exception ex)
        {
            if (!isConnected)
            {
                this.Dispatcher.Invoke((Action)(() =>
                {
                    lblError.Text = "SERVER IS OFFLINE ... !\n" + ex.Message;
                }));
                return false;
            }
            else
                return true;
        }
    }

где моя проблема?