client can not connect againt to my Socket Server - VB.NET - vb.net

Question

I have a thread and a socket server for listening to client. Client software is not for me and it is a Laboratory Software that sends data to my program.
when listening starts there is no problem but when the client software is closed and reopened, that can not send any data to my software.
My listener must be run every time like a service.
This is my code:
Delegate Sub WriteMsgHandle(ByVal Msg As String)
Dim handler As WriteMsgHandle
Dim THS As ThreadStart
Dim TH As Thread
Private Sub btnListen_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnListen.Click
Try
btnListen.Enabled = False
THS = New ThreadStart(AddressOf Listen)
TH = New Thread(THS)
TH.Start()
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
Public Sub Listen()
Dim bytesReceived As Integer = 0
Dim recv() As Byte = New Byte(1) {}
Dim clientSocket As Socket
Dim listenerSocket As New Socket _
(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
Dim IPHost As IPHostEntry = Dns.GetHostEntry(Dns.GetHostName())
Dim localadd As IPAddress = IPAddress.Parse(txt_ip.Text)
Dim ipepServer As IPEndPoint = New IPEndPoint(localadd, txt_port.Text)
handler = AddressOf WriteMsg
listenerSocket.Bind(ipepServer)
listenerSocket.Listen(-1)
clientSocket = listenerSocket.Accept()
Dim msgcount As Integer = 0
If clientSocket.Connected Then
MsgBox("Connected")
Do
bytesReceived = clientSocket.Receive(recv)
Dim Msg As String
Msg = Encoding.ASCII.GetString(recv)
Invoke(handler, Msg)
Loop While bytesReceived <> 0
End If
End Sub

Answer 1

You're only accepting once. You need to accept in a loop.
If clientSocket.Connected Then why did you add this? Delete that check. The socket was just accepted so it is connected. Even if it was disconnected do you want to just ignore that error condition?!
The receive loop is correct.
You probably want to start each accepted client on a new thread (or use async IO).