Startup.cs

using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using System;


namespace monacoEditorCSharp
{

    public class Startup
    {
        public Startup(IWebHostEnvironment env)
        {
            var builder = new ConfigurationBuilder().SetBasePath(env.ContentRootPath);
            Configuration = builder.Build();
        }
        public IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {

            services.AddCors(options =>
            {
                options.AddPolicy("CorsPolicy",
                    builder => builder.AllowAnyOrigin()
                    .AllowAnyMethod()
                    .AllowAnyHeader());
            });
            services.AddMvc(options => { options.EnableEndpointRouting = true; })
            .AddJsonOptions(options =>
            {
                options.JsonSerializerOptions.WriteIndented = true;
                options.JsonSerializerOptions.PropertyNameCaseInsensitive = true;
            });


            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
            services.AddRouting(options => options.LowercaseUrls = true);


            string domain = $"https://{Configuration["Auth0:Domain"]}/";
            services.AddAuthentication(options =>
            {
                options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;

            }).AddJwtBearer(options =>
            {
                options.Authority = domain;
                options.Audience = Configuration["Auth0:ApiIdentifier"];
            });


        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IServiceProvider serviceProvider, IHttpContextAccessor accessor)
        {

            if (env.EnvironmentName == "Development")
            {
                app.UseDeveloperExceptionPage();

            }

            app.UseAuthentication();

            app.UseCors(options =>
            {
                options.AllowAnyOrigin();
                options.AllowAnyHeader();
                options.AllowAnyMethod();
            });

            app.UseHttpMethodOverride();
            DefaultFilesOptions DefaultFile = new DefaultFilesOptions();
            DefaultFile.DefaultFileNames.Clear();
            DefaultFile.DefaultFileNames.Add("monacoeditor.html");
            app.UseDefaultFiles(DefaultFile);
            app.UseStaticFiles();
            app.UseRouting();
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });

        }


    }
}