Restart Signalr and Owin self host

I am writing a wpf application where the user should be able to start and stop a web server. I'm using owin, signalr, and nancy-fx for my server. The problem I'm having is that after stopping the web server I can not start it again. I get a timeout error when trying to do _hubConnection.Start().Wait(). From what I've found online I am stopping the server correctly but maybe not?

System.AggregateException
  HResult=0x80131500
  Message=One or more errors occurred.
  Source=mscorlib
  StackTrace:
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.Wait()
   at WebServer.StartSocketConnection() in C:\...\WebServer.vb:line 102
   at MainWindow.mnuEnableWebServer_OnClick(Object sender, RoutedEventArgs e) in C:\...\MainWindow.xaml.vb:line 320
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
   at System.Windows.Controls.MenuItem.InvokeClickAfterRender(Object arg)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

Inner Exception 1:
TimeoutException: Transport timed out trying to connect

This is my webserver class

Public Class WebServer

    Dim _hubConnection As HubConnection
    Dim _hubProxy As HubProxy
    Dim _server As IDisposable
    Private Shared _instance As WebServer

    Private Property Bootstrapper As CustomBootstrapper
    Public Property LocalAddress As String
    Public Property Port As Integer
    Public ReadOnly Property Url As String
        Get
            Return String.Format("http://{0}:{1}/", LocalAddress, Port)
        End Get
    End Property

    Public Shared ReadOnly Property Instance As WebServer
        Get
            If _instance Is Nothing Then
                _instance = New WebServer()
            End If
            Return _instance
        End Get
    End Property

    Public Sub New()
        LocalAddress = Dns.GetHostEntry(Dns.GetHostName()).AddressList().ToList().Last().ToString()
        Port = 8080
        GlobalHost.Configuration.DisconnectTimeout = TimeSpan.FromSeconds(6)
    End Sub

    Public Sub StartHost()
        Bootstrapper = New CustomBootstrapper()

        _server = WebApp.Start(Url, Function(app)
                                        app.Map("/signalr", Function(map)
                                                                map.UseCors(CorsOptions.AllowAll)
                                                                Dim hubConfiguration = New HubConfiguration()
                                                                map.RunSignalR(hubConfiguration)
                                                            End Function).UseNancy(Function(options)
                                                                                       options.Bootstrapper = Bootstrapper
                                                                                   End Function)
                                    End Function)
    End Sub

    Public Sub StartSocketConnection()
        _hubConnection = New HubConnection(Url)
        _hubProxy = _hubConnection.CreateHubProxy("myHub")
        _hubConnection.Start().Wait()
    End Sub

    Public Sub StopServer()
        _hubConnection.Stop()
        _server.Dispose()
    End Sub

End Class

And this is how I call my start and stop methods

Private Sub mnuEnableWebServer_OnClick(sender As Object, e As RoutedEventArgs)
    WebServer.Instance.StartHost()
    WebServer.Instance.StartSocketConnection()
End Sub

Private Sub mnuDisableWebServer_OnClick(sender As Object, e As RoutedEventArgs)
    WebServer.Instance.StopServer()
End Sub