Error: The operation was cancelled

https://github.com/mindofai/SignalRChat running on local IIS

Used ngrok to access it using a public URL

  hubConnection = new HubConnectionBuilder()
         .WithUrl($"http://randomsubdomain.ngrok.io" + "/chatHub")
         .Build();

Ran the below command to setup ngrok:

ngrok.exe http 44398

I see requests in ngrok terminal when click on 'connect' but nothing happens in the app.

After few minutes of trying I get the below error: