failed to make Windows Desktop UI App in .Net Framework 4.8 SignalR client to connect to .Net Core SignalR Server

Question

I can make IIS ASP.NET .Net Framework 4.8 SignalR client to connect to .Net Core SignalR Server.

But I failed to make Windows Desktop UI App in .Net Framework 4.8 SignalR client to connect to .Net Core SignalR Server.

.Net Core SignalR Server:
        IIS ASP.Net Core 8.0,
        Microsoft.AspNetCore.SignalR 1.1.0,
        Microsoft.AspNetCore.SignalR.Core 1.1.0,
        Angular,
        Javascript (Browser) successfully made SignalR connection to .Net Core SignalR Server

SignalR Client 1:
    IIS ASP.NET 4.8,
    Microsoft.AspNetCore.SignalR.Client 8.0.0.0,
    Microsoft.AspNetCore.SignalR.Client.Core 8.0.0.0,
    successfully made SignalR connection to .Net Core SignalR Server

SignalR Client 2:
   Windows C# Desktop UI App in .NET Framework 4.8,
   Microsoft.AspNetCore.SignalR.Client 8.0.0.0,
   Microsoft.AspNetCore.SignalR.Client.Core 8.0.0.0,
   Failed to make SignalR connection to .Net Core SignalR Server

Connection = new HubConnectionBuilder()
    .WithUrl("http://localhost/QMOSRFactor/rfactor",
        options => {
            options.Transports = HttpTransportType.WebSockets;
        })
    .WithAutomaticReconnect()
    .Build();


await Connection.StartAsync();

For SignalR Client 2, after calling await Connection.StartAsync(), nothing happened. No error in Visual Studio Output. No exceptions throwed.

If I wrapped the above code in netstandard2.0 library. Reference this library in Client 2 project. Nothing happened. No error in Visual Studio Output. No exceptions.