Server/Client Not all connecting after server diconnect

[85ssp]

I am creating a small server client program that is meant for up to 70 connections from 70 different computers on a network.

Everything in the program functions correctly except when testing operations with a server crash, the clients go into a disconnected state and wait for the server to come back up.

Once the server is up the clients attept to connect. 75% of the time all clients connect and there connect message is accepted and parsed without a problem then they are added to a clients hash table, the other 25% the server still connects all clients but thier connect message is not accepted or parsed so they are not added to the client hash table, maybe missine one or two, the clients sent the connect string but its as if the server never got the message. I have no clue how to remedy this. Here is some sample code hopefully enough to explain the process. Thanks to all I'm losing my mind on this.

Server:

Private listener As TcpListener
Private listenerthread As Threading.Thread
Public Shared statusdict As New Hashtable
Public Shared clients As New Hashtable
 
 Private Sub AdminForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
 
        '**********************************************************************
        'SOCKET CONNECTION SECTION 
        listenerthread = New Threading.Thread(AddressOf DoListen)
        listenerthread.Start()
 
        Updatestatus("Listener Started")
        '**********************************************************************
 
  End Sub
 
 Private Sub DoListen()
        Try
            ' Listen for new connections.
          listener = New TcpListener(System.Net.IPAddress.Any, config.PortNumber)
            listener.Start()
 
            Do
                ' Create a new user connection using TcpClient returned by
 
                Dim client As New UserConnection(listener.AcceptTcpClient)
 
                ' Create an event handler to allow the UserConnection to communicate with the window.
 
                AddHandler client.LineReceived, AddressOf OnLineReceived
                Updatestatus("New connection found: waiting for log-in")
            Loop Until False
        Catch ex As Exception
'error handling
        End Try
    End Sub
 
 
 Private Sub ConnectUser(ByVal workstation As String, ByVal sender As UserConnection)
        Try
            If Not clients.Contains(workstation) Then
 
                sender.WS = workstation
                '
                'adds connected ws to hashtable
                clients.Add(workstation, sender)
                'sends connected to client
                ReplyToSender("CONNECTED|" sender)
            End If
        Catch ex As Exception
            'MsgBox(Environment.StackTrace.ToString)
         End Try
    End Sub
 
Private Sub OnLineReceived(ByVal sender As UserConnection, ByVal data As String)
        Dim dataArray() As String
        Dim clientcount As Integer = clients.Count
        ' Message parts are divided by "|"  Break the string into an array accordingly.
        dataArray = data.Split(Chr(124))
        ' dataArray(0) is the command. 
        Try
 
            Select Case dataArray(0)
                Case "CONNECT"
                    'when connect is sent from client, the ws is the dataarray(1)
                    Try
                        Updatestatus(dataArray(1) & " has connected.")
                        ConnectUser(dataArray(1), sender)
                      Catch ex As Exception
                              'some error processing
                      End Try
 
 Case "RECSTATUS"
                    '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'creates and updates a separete hashtable for display of ws status
 
                    Try
                        If Not statusdict.ContainsKey(sender.WS) Then
                            statusdict.Add(sender.WS, dataArray(3))
                        Else
                            statusdict.Item(sender.WS) = dataArray(3)
                        End If
                      Catch ex As Exception
                        MsgBox(ex)
                        WriteError.WriteErrorFile(Me.Name.ToString, ex.ToString(), True, True, True, True)
                    End Try
            End Select
        Catch ex As Exception
           ' WriteError.WriteErrorFile(Me.Name.ToString, ex.ToString(), True, True, True, True)
        End Try
End select 
End sub
 
    Private Sub Updatestatus(ByVal statusmessage As String)
        lstStatus.Items.Add(statusmessage)
        'lstStatus.SelectedIndex = lstStatus.Items.Count - 1
    End Sub
 
Public Shared Sub ReplyToSender(ByVal strmessage As String, ByVal sender As UserConnection)
        Try
            sender.SendData(strmessage)
        Catch ex As Exception
            'MsgBox("1 " & Environment.StackTrace.ToString)
        End Try
 
End Sub

Client:

   Dim currentstatus As String = ""
    Dim oldstatus As String = ""
    Dim conncount As Integer = 0
 
    Const READ_BUFFER_SIZE As Integer = 255
    Private client As TcpClient
    Private readbuffer(READ_BUFFER_SIZE) As Byte
 
Private Sub clientform_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        MakeConnection(Nothing)
End Sub
 
Public Sub MakeConnection(ByVal callingfunc As String)
 
        Try
            If callingfunc <> "MarkAsDisconnected" Then
                Me.Show()
            End If
 
            Do
                Try
                    client = New TcpClient()
                    client.Connect("localhost", 6000)
                    Me.Enabled = True
                    Label1.BackColor = Color.Green
                Catch e As Exception
                    Label1.BackColor = Color.Red
                End Try
            Loop Until client.Connected = True
 
            ' Start an asynchronous read invoking DoRead to avoid lagging the user
            ' interface. 
 
            client.GetStream.BeginRead(readbuffer, 0, READ_BUFFER_SIZE, AddressOf DoRead, Nothing)
 
            ' If callingfunc <> "MarkAsDisconnected" Then 'attempt to make it recheck for connection and reconnect
            SendCMD("CONNECT|" & System.Environment.MachineName)
 
 
 
        Catch e As Exception
             Me.Dispose()
        End Try
    End Sub
 
    Private Sub DoRead(ByVal ar As IAsyncResult)
        Dim BytesRead As Integer
        Dim strMessage As String
        Try
            ' Finish asynchronous read into readBuffer and return number of bytes read.
            BytesRead = client.GetStream.EndRead(ar)
            If BytesRead < 1 Then
                ' If no bytes were read server has close.  Disable input window.
               MarkAsDisconnected()
               Exit Sub
            End If
            ' Convert the byte array the message was saved into, minus two for the
            ' Chr(13) and Chr(10)
 
            strMessage = Encoding.ASCII.GetString(readbuffer, 0, BytesRead - 2)
 
            ProcessCommands(strMessage)
 
            ' Start a new asynchronous read into readBuffer.
            client.GetStream.BeginRead(readbuffer, 0, READ_BUFFER_SIZE, AddressOf DoRead, Nothing)
 
        Catch e As Exception
           MarkAsDisconnected()
        End Try
    End Sub
 
 Private Sub MarkAsDisconnected()
               conncount = 1
        oldstatus = currentstatus
               MakeConnection("MarkAsDisconnected")       
End Sub
 
    Private Sub SendCMD(ByVal data As String)
        Dim writer As New IO.StreamWriter(client.GetStream)
        writer.Write(data & vbCr)
        writer.Flush()
    End Sub
 
Private Sub ProcessCommands(ByVal strMessage As String)
        Dim dataArray() As String
        ' Message parts are divided by "|"  Break the string into an array accordingly.
        dataArray = strMessage.Split(Chr(124))
 
        If dataArray(0) = "CONNECTED" Or dataArray(0) = "LOCKED" Or _
        dataArray(0) = "LOGGEDIN" Or dataArray(0) = "LOGGEDOUT" Then
            currentstatus = dataArray(0)
        End If
 
 
        Select Case dataArray(0)
            Case "CONNECTED"
                Label1.BackColor = Color.Green
                If conncount = 0 Then
                    'sends status connected, but dont want to log on recon
                    SendCMD("RECSTATUS|CONNECTED|" & System.Environment.MachineName.ToString)
 
                ElseIf conncount = 1 Then
                    currentstatus = oldstatus
                    SendCMD("RECSTATUS|" & currentstatus & "|" & System.Environment.MachineName.ToString)
                    conncount = 0
                End If
 
Case Else
                MsgBox("no message")
 
        End Select
    End Sub

Hopefully this is enough to help understand. I appreciate everything anyone can help me with.