Startup.cs

using AuthService.Services;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.IdentityModel.Logging;

namespace AuthService
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();
            services.AddCors(options =>
            {
                options.AddPolicy("AllowAngularDevClient",
                  builder =>
                  {
                      builder
                      .WithOrigins("http://localhost:4200")
                      .AllowAnyHeader()
                      .AllowAnyMethod();
                  });
            });
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env, DataContext dataContext)
        {
            app.UseCors("AllowAngularDevClient");
            app.UseRouting();

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