How to connect to an MQTTServer in a Blazor app published to IIS?

Trying to get over this bump to begin getting my Home Automation projects going.

• I created a Blazor Server App using the template in VS 2022.
• Added a menu item called "Lights" that brings up a Lights.razor page.
• In it, I added the below MQTTServer code:

@code {
    protected override void OnInitialized()
    {
        MQTTService.MQTTServer_Start();
    }

    async void MQTTServer_Start()
    {
        var options = new MqttServerOptionsBuilder().WithDefaultEndpoint().WithDefaultEndpointPort(1111);
        var server = new MqttFactory().CreateMqttServer(options.Build());
        server.InterceptingPublishAsync += Server_InterceptingPublishAsync;
        await server.StartAsync();
        Task Server_InterceptingPublishAsync(InterceptingPublishEventArgs arg)
        {
            var payload = arg.ApplicationMessage?.Payload == null ? null : Encoding.UTF8.GetString(arg.ApplicationMessage?.Payload);
            Debug.WriteLine(arg.ClientId);
            return Task.CompletedTask;
        }
    }
}

• I hit run. It seems to launch its own web server, likely IISExpress; not sure.
• The Blazor template web site comes up fine.
• I click the Lights menu item I added, the Light page comes up fine.
• The page runs MQTTServer as per the above code.
• I run my MicroPython MQTTClient code from my Raspberry Pico W and successfully connect with that MQTTServer.
• I stop the Blazor app.
• I publish it to my IIS Server on this same machine.
• I goto that IIS Hosted Blazor app with Chrome.
• Click on the Lights menu item.
• I run my MicroPython MQTTClient code from my Raspberry Pico W and it fails with the error:
  "Traceback (most recent call last):
  File "umqttsimple.py", line 61, in connect
  OSError: [Errno 103] ECONNABORTED"

Anyone has any idea why it works from VS but fails from IIS?
Any good techniques out there I could follow to get over that bump?