Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace AskForMasksCoreVue
{
    public class Startup
    {
        private readonly string MyAllowSpecificOrigins = "_myAllowSpecificOrigins";

        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllersWithViews();
            services.AddCors(options =>
            {
                options.AddPolicy(MyAllowSpecificOrigins,
                    builder =>
                    {
                        builder.WithOrigins("*");
                    });
            });
            services.Add(new ServiceDescriptor(typeof(IDataProvider), typeof(CosmosDbDataProvider), ServiceLifetime.Singleton));
            services.Add(new ServiceDescriptor(typeof(IGeocodingProvider), typeof(AzureMapsGeocodingProvider), ServiceLifetime.Singleton));
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            //if (env.IsDevelopment())
            //{
                app.UseDeveloperExceptionPage();
            //}
            //else
            //{
            //    app.UseExceptionHandler("/Home/Error");
            //    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
            //    app.UseHsts();
            //}

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCors(MyAllowSpecificOrigins);
            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Default}/{action=AllRequests}");
            });
        }
    }
}