Vb.net application connect to multiple server via TCP/IP - vb.net

Question

I made a Winforms application to work with 4 different machines by connecting with them via TCP/IP. Somehow, the connection sometimes seems disconnected and reconnecting after a short while. May I know is it I used too much TCP client and caused them congested??
Below is the function/method to connect those machine...with 4 of them different function names to connect each of the machine, but the code is more or less the same:
Public Async Sub connect_Machine_Ethernet(ByVal mainForm As Form1)
If Machine_COMPort.IsOpen Then
Machine_COMPort.Close()
End If
If (IsNothing(Machine_client)) Then
'do nothing, since obj is not created
Else
Try
Machine_client.GetStream.Close()
Machine_client.Close()
Catch exp As Exception
End Try
End If
Try
Machine_client = New TcpClient
Machine_client.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, True)
Dim result = Machine_client.BeginConnect(Machine_ModuleIP_txt.Text, CInt(Machine_ModulePort_txt.Text), Nothing, Nothing)
result.AsyncWaitHandle.WaitOne(TimeSpan.FromSeconds(1))
Machine_client.GetStream.BeginRead(Machine_ethernet_buffer, 0, Machine_ethernet_buffer.Length, AddressOf Machine_TCP_read, Machine_ethernet_buffer)
DisplayMsg("Machine Ethernet connection established")
manual_connection_LED.StateIndex = 3
Machine_client_isConnected = True
Machine_TCP_Reconnect_btn.Invoke(Sub() Machine_TCP_Reconnect_btn.Visible = False)
Catch ex As Exception
DisplayMsg("Error : Unable to connect to the Machine Ethernet connection")
manual_connection_LED.StateIndex = 0
Machine_client_isConnected = False
If (IsNothing(Machine_client)) Then
'do nothing, since obj is not created
Else
Try
Machine_client.GetStream.Close()
Machine_client.Close()
Catch exp As Exception
End Try
End If
End Try
End Sub
'Read Machine TCP message
Sub Machine_TCP_read(ByVal ar As IAsyncResult)
Try
Dim buffer() As Byte = ar.AsyncState
Dim bytesRead As Integer = Machine_client.GetStream.EndRead(ar)
Dim Message As String = System.Text.Encoding.ASCII.GetString(Machine_ethernet_buffer, 0, bytesRead)
If Message = "" Then
'----check connection
If Machine_client.Connected Then
Machine_client.Close()
connect_Machine_Ethernet(Me)
End If
Else
DisplayMsg("Input Received from machine : " & Message)
Process_machine_Feedback(Message) 'perform any data logic from the message
Machine_client.GetStream.BeginRead(Machine_ethernet_buffer, 0, Machine_ethernet_buffer.Length, AddressOf Machine_TCP_read, Machine_ethernet_buffer)
End If
Catch ex As Exception
DisplaySystemMsg(ex.Message)
DisplayMsg("Marking machine Ethernet disconnected from the server")
manual_connection_LED.StateIndex = 0
Machine_client_isConnected = False
Exit Sub
End Try
End Sub
'Send message to TCP
Public Sub Machine_TCP_send(ByVal str As String)
Try
sWriter = New StreamWriter(Machine_client.GetStream)
sWriter.WriteLine(Chr(2) & str & Chr(3)) 'add prefix suffix
sWriter.Flush()
DisplayMsg("Message send to the machine via TCP: " & str)
Catch ex As Exception
DisplayMsg("Error : Message failed to send to themachine!")
End Try
End Sub