.NET Core 2.0 App - MVC works when debugging but not in docker container

Question

I have built a very simple .NET Core app (target framework = 2.0), which runs fine when debugging (localhost).....but when I run in docker container on prod server, everything works except the MVC routes.

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }

    app.UseStaticFiles();

    app.UseMvcWithDefaultRoute();

    app.Run(async (context) =>
    {
        await context.Response.WriteAsync("Environment name: " + env.EnvironmentName);
    });
}

app.UseStaticFiles() works fine....as /index.html path returns the relevant file. Also the app.Run() command works, and returns for all routes that are not calls for static files......Im assuming because the app.UseMvcWithDefaultRoute(); middleware is not being recognized so its passing to the next/final middleware.

Below is my HomeController.cs

public class HomeController : Controller
{
    public string Index()
    {
        return "Hello world!!....from Controllers(folder)/HomeController(folder)/Index(function)";
    }
}

When I request route IP/home/index, it should come back with the Hello World message......it does when debugging but not when running in docker container

Below is my docker file:

FROM microsoft/aspnetcore-build:2.0 AS build-env
WORKDIR /app

# Copy csproj and restore as distinct layers
COPY *.csproj ./
RUN dotnet restore

# Copy everything else and build
COPY . ./
RUN dotnet publish -c Release -o out

# Build runtime image
FROM microsoft/aspnetcore:2.0
WORKDIR /app
COPY --from=build-env /app/out .
ENTRYPOINT ["dotnet", "mpx.dll"]

UPDATE: I changed HomeController.cs Index method to below....but it didnt help

    public class HomeController : Controller
    {
        [HttpGet]
        public string Index()
        {
            return "Hello world!!....from Controllers(folder)/HomeController(folder)/Index(function)";
        }
    }