Why Angular + ASP.NET Core SPA is not working on network Ubuntu VM?

Issue

I am deploying a ASP.NET 5, Angular 11, SPA to a network location on a Ubuntu 20.04 local VM. I published the app as linux native self contained. Web API and Client app have same url/port, it's working on dev machine.

I have this in appsettings.json:

"ApplicationUrl": "http://ubuntu1:5000",

"Kestrel": {
  "Endpoints": {
    "Http": {
      "Url": "http://192.168.0.120:5000"
    },
  }
},

I can see the index.html page with the app loading message but the problem is that the angular part is not starting. Is there some logs I can check somewhere ? The web app itself seems to be working fine, as I tested the web api from Postman.

I have in the .net code:

services.AddSpaStaticFiles(configuration =>
        {
            configuration.RootPath = "ClientApp/dist";
        });
//...
app.UseSpa(spa =>
        {


            spa.Options.SourcePath = "ClientApp";

            if (env.IsDevelopment())
            {
                spa.UseAngularCliServer(npmScript: "start");                    
            }
        });

Also in /etc/systemd/system/modulo.service on the VM I have:

[Unit]
Description=Modulo ASP .NET Web Application
[Service]
WorkingDirectory=/var/modulo
ExecStart=/var/modulo/Modulo
Restart=always
RestartSec=10
SyslogIdentifier=modulo-app
User=paul (I also tried with www-data)
Environment=ASPNETCORE_ENVIRONMENT=Production
[Install]
WantedBy=multi-user.target

I get no errors when restarting the service on Ubuntu. And the status is active (running).

Solution

It seems I had to also use:

        app.UseStaticFiles(new StaticFileOptions
        {
            FileProvider = new PhysicalFileProvider(
                Path.Combine(Directory.GetCurrentDirectory(), "ClientApp", "dist")),
            RequestPath = ""
        });

Answered By - Paul Manson