Asp.Net Core Blazor SignalR not working as expected in IIS

(Visual Studio 2019. Blazor WebAssembly with .NET 5.0. NuGget packages updated. WebSocket enabled) Hi I have a .NET 5 blazor wasm project, it works on local perf, but when I publish it on IIS not working as expected.

https://github.com/equirev73/Languages

After a few minutes it waits for some time and then it no longer navigates. In Chrome + F12 I see requests “wss” such as IIS Express. But now its status is pending.

LanguagesList.razor (only code)

@code {
      List<ProgramingLanguages> languages;
      private HubConnection hubConnection;

      protected override async Task OnInitializedAsync()
      {
          hubConnection = new HubConnectionBuilder()
              .WithUrl(NavigationManager.ToAbsoluteUri("/languageshub"))
            .Build();

          hubConnection.On("ReceiveMessage", () =>
          {
            CallAllLanguages();
            StateHasChanged();
          });

          await hubConnection.StartAsync();
          await GetAllLanguages();
      }

      private void CallAllLanguages()
      {
          Task.Run(async () => await GetAllLanguages());
      }

      protected async Task GetAllLanguages()
      {
          languages = await   HttpClient.GetFromJsonAsync<List<ProgramingLanguages>>("api/ProgramingLanguages");
          StateHasChanged();
      }

      public void Dispose()
      {
          _ = hubConnection.DisposeAsync();
      }
}

Thanks in advance

[equirev73]

Thank you @BrennanConroy . I was checking on Develpment and IIS. Now it works even without SSL. I was very worried. Now I trust Blazor Wasm + SignalR again. I will study the tutorial that you mentioned. Maybe one day I can help someone. If an error should appear, I will be file an issue there. So they take a look at it.

Thank you @BrennanConroy again. Thank you @Ariansh . Thank you @pranavkm.

[BrennanConroy]

@equirev73 The error you showed above about the “delegate target no longer available” is an issue with the WASM Runtime at https://github.com/dotnet/runtime. If you have a small consistent repro it might be a good idea to file an issue there for them to look at.

As far as getting rid of that error, you are missing @implements IDisposable from your LanguageList.razor page which means the SignalR client is never disposed and you have a bunch of background WebSocket clients running (which is part of the reason for the error you see).

Side-note: You can use DisposeAsync in 5.0 with @implements IAsyncDisposable and we have a tutorial for Blazor Wasm + SignalR at https://docs.microsoft.com/aspnet/core/tutorials/signalr-blazor-webassembly?view=aspnetcore-5.0&tabs=visual-studio