DataWriter StoreAsync() throws exception

I got an issue as part of remote websocket server accessing ('ws://172.17.35.104:8080/WebsocketHttpListenerDemo') from UWP app.

DataWriter StoreAsync() throws exception . A method was called at an unexpected time. (Exception from HRESULT: 0x8000000E)

please refer the below sample code (client):

            private async void Button_Click(object sender, RoutedEventArgs e)
            {
                Connect("ws://172.17.35.104:8080/WebsocketHttpListenerDemo").Wait();
            }

            public async Task Connect(string uri)
            {
                await Task.Delay(100); //wait for a sec, so server starts and ready to accept 
                // await Task.Delay(TimeSpan.FromSeconds(1));
                messageWebSocket = new Windows.Networking.Sockets.MessageWebSocket();
                messageWebSocket.Control.MessageType = Windows.Networking.Sockets.SocketMessageType.Utf8;
                messageWebSocket.MessageReceived += WebSocket_MessageReceived;
                messageWebSocket.Closed += WebSocket_Closed;
                try{
                    Task connectTask = messageWebSocket.ConnectAsync(new Uri(uri)).AsTask();
                    await connectTask.ContinueWith(_ => this.SendMessageUsingMessageWebSocketAsync("Hello, World!"));
                    await Task.Delay(1000);
                }
                catch (Exception ex)
                {}
                finally
                { }
            }
            private async Task SendMessageUsingMessageWebSocketAsync(string message)
            {
                try
                {
                    using (var dataWriter = new DataWriter(this.messageWebSocket.OutputStream))
                    {
                    dataWriter.WriteString(message);
                    await dataWriter.StoreAsync();
                    dataWriter.DetachStream();
                    }
                }
                catch (Exception ex)
                {}
            }

server side code:

WebsocketServer websocketServer = new WebsocketServer(); websocketServer.Start("http://172.17.35.104:8080/WebsocketHttpListenerDemo/");

            ------------
            public async void Start(string httpListenerPrefix)
            {
                HttpListener httpListener = new HttpListener(); 

                httpListener.Prefixes.Add(httpListenerPrefix);  

                httpListener.Start();   

                Console.WriteLine("Listening...");

                while (true){
                        HttpListenerContext httpListenerContext = await httpListener.GetContextAsync();

                        ProcessRequest(httpListenerContext);  
                        }
            }

            private async void ProcessRequest(HttpListenerContext httpListenerContext)
            {
                WebSocketContext webSocketContext = await httpListenerContext.AcceptWebSocketAsync(subProtocol: null);

                WebSocket webSocket = webSocketContext.WebSocket;

                byte[] receiveBuffer = new byte[1024];

                while (webSocket.State == WebSocketState.Open)
                {
                    WebSocketReceiveResult receiveResult = await webSocket.ReceiveAsync(new ArraySegment<byte>(receiveBuffer), 
                                                        CancellationToken.None);    
                }  
            }   

Please refer the Official WebSocket sample and look into the Run the sample part in the sample README.md file to Configure your web server.

I tried to use the sample provided web server scripts and connect to the "ws://localhost/WebSocketSample/EchoWebSocket.ashx" server address to test your above code, it can work well. You can also try the Official WebSocket sample or the sample localhost server.