C# – An established connection was aborted by the software in host machine

I couldn't find my answer in some topics.
I have a client/server code.
I have a client side and server side in a separate programs .
This is client side:

 try
        {

        byte[] bytes = new byte[1024];
        string text = "";
        text = uitbtextmsg.Text;
        byte[] msg = Encoding.ASCII.GetBytes(text);
        int bytesSent = User.Send(msg);
        int bytesRec = User.Receive(bytes);

        uirtbmsg.Text = uirtbmsg.Text + '\n' + " " + text;
        }
        catch (Exception E)
        {
            MessageBox.Show(E.ToString());
        }

This is for when I am connected to server and I want to chat with that socket.
This is my connection:

            byte[] bytes = new byte[1024];
            IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
            IPAddress ipAddress = ipHostInfo.AddressList[2];
            IPEndPoint remoteEP = new IPEndPoint(ipAddress, 11000);
            Socket User = new Socket(AddressFamily.InterNetwork,
            SocketType.Stream, ProtocolType.Tcp);
            User.Connect(remoteEP);

And this is server side:

 byte[] bytes = new Byte[1024];
        IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
        IPAddress ipAddress = ipHostInfo.AddressList[2];
        IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);
        Socket listener = new Socket(AddressFamily.InterNetwork,
        SocketType.Stream, ProtocolType.Tcp);
        try
        {
            listener.Bind(localEndPoint);
            listener.Listen(10000);
            while (true)
            {
                Socket handler = listener.Accept();
                data = null;
                while (true)
                {
                    bytes = new byte[1024];
                    int bytesRec = handler.Receive(bytes);
                    data += Encoding.ASCII.GetString(bytes, 0, bytesRec);
                    TextRecieved = data;
                    Thread textbox = new Thread(new ThreadStart(WriteInReachTextBox));
                    textbox.Start();
                    break;
                }

                //uirtbreport.Text = data;
                byte[] msg = Encoding.ASCII.GetBytes(data);
                handler.Send(msg);
                handler.Shutdown(SocketShutdown.Both);
                handler.Close();
            }

        }
        catch (Exception e)
        {
            MessageBox.Show(e.ToString());
        }

When client first sends a message to server this procedure is ok! But when it send another message it will throw an Exception:

System.Net.Socket.SocketException(0x80004005):An established
connection was aborted by the software in your host machine at
System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32
size, SocketFlags socketFlags) at
System.Net.Sockets.Socket.Receive(Byte[] buffer)\r\n at
Client.Form1.uibtnsendmsg_Click(Object sender, EventArgs e) in …