SignalR Core, error: The 'Sec-WebSocket-Accept' header value 'u1mOHwcpjPm7txGcxCm1jVmOgjo=' is invalid

I'm trying to implement SignalR Core in a .Net core 2.0 Web app, and implement client side in a Xamarin.Android application. I created a fresh .Net core 2.0 Web app solution and imported Microsoft.AspNetCore.SignalR and setup the Startup.cs file like in this sample

https://github.com/aspnet/SignalR-samples/blob/master/ChatSample/ChatSample/Startup.cs

My code:

public class Startup
{

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddSignalR();
    }


    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        app.UseFileServer();

        app.UseSignalR(routes =>
        {
            routes.MapHub<ChatHub>("chat");
        });
    }
}

This project is deployed to Amazon Elastic Bean Stalk.

On the client side, I have imported Microsoft.AspNetCore.SignalR.Client and I initialize a connection like in this sample

https://github.com/aspnet/SignalR-samples/blob/master/XamarinAndroidChatClient/XamarinAndroidChatClient/MainActivity.cs

My code:

    public async override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        hubConnection = new HubConnectionBuilder()
                .WithUrl("http://*******.eu-central-1.elasticbeanstalk.com/chat")
                .Build();
        try
        {
            await hubConnection.StartAsync();
        }
        catch(Exception ex)
        {
            System.Diagnostics.Debug.WriteLine(ex.StackTrace);
        }
    }

But .StartAsync() throws this exception:

{System.Net.WebSockets.WebSocketException (0x80004005): The 'Sec-WebSocket-Accept' header value 'LNqQiPhES/zOwW10TMji4AVvvoA=' is invalid. at System.Net.WebSockets.WebSocketHandle.ValidateAndTrackHeader (System.String targetHeaderName, System.String targetHeaderValue, System.String foundHeaderName, System.String foundHeaderValue, System.Boolean& foundHeader) [0x0002c] in <6c708cf596db438ebfc6b7e012659eee>:0 `

I found this post which was related to Amazon ELB and setting up websockets

(Elastic Beanstalk stripping Sec-WebSocket-Accept header)

Also found this post with same problem

(https://forums.aws.amazon.com/thread.jspa?messageID=613220)

As in this post, things are working fine if I choose "LongPolling" as transport

        hubConnection = new HubConnectionBuilder()
                .WithUrl("http://*******.eu-central-1.elasticbeanstalk.com/chat")
                .WithTransport(TransportType.LongPolling)
                .Build();

This guy was suggested to switch LoadBalancer listeners from HTTP to TCP, I tried this, but issue is still remaining Also I read a suggestion to install websockets in ISS on AWS Management Console, but I can't find this option anywhere?

Any kind of help or suggestions are appreciated

You'll need to log onto the Elastic BeanStalk server and enable the Websocket Protocol on in the server roles in Server Manager, this fixed it for me.