Startup.cs

using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.IdentityModel.Tokens;
using System.Text;
using USMBQuizzAPI.Authentication;

namespace USMBAPI
{
    public class Startup
    {
        private readonly string _key = "js3sRyc5Ir6RIU1wYiwhpNmeVpQbPysx";

        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.AddControllers();

            services.AddCors(c =>
            {
                c.AddDefaultPolicy(options => {
                    options.AllowAnyOrigin();
                    options.AllowAnyHeader();
                    options.AllowAnyMethod();
                });
            });

            services.AddSingleton<IJwtAuthenticationManager>(new JwtAuthenticationManager(Configuration));

            services.AddAuthentication(x =>
            {
                x.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                x.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;

            }).AddJwtBearer(x => {
                x.RequireHttpsMetadata = false;
                x.SaveToken = true;
                x.TokenValidationParameters = new TokenValidationParameters
                {
                    ValidateIssuerSigningKey = true,
                    IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(_key)),
                    ValidateIssuer = false,
                    ValidateAudience = false
                };
            });

        }

        // 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();
            }

            app.UseRouting();

            app.UseCors(options => options.AllowAnyOrigin());

            app.UseAuthentication();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}