RedirectLoop

Startup.cs

public class Startup
    {
        public Startup(IHostingEnvironment env)
        {
			var builder = new ConfigurationBuilder().AddJsonFile("appsettings.json");
            Configuration = builder.Build();
        }

        public IConfigurationRoot Configuration { get; set; }

        public void ConfigureServices(IServiceCollection services)
        {
			services.AddAuthorization(options =>
			{
				options.AddPolicy("IsDeveloper", builder =>
				{
					builder.RequireAuthenticatedUser();
					builder.RequireClaim("FakeClaim", "NobodyWillHaveAClaimLikeThis");
				});
			});
			services.AddMvc();
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            loggerFactory.AddConsole();

			app.UseCookieAuthentication(options =>
			{
				options.AutomaticAuthenticate = true;
				options.AutomaticChallenge = true;
			});
			app.UseOpenIdConnectAuthentication(options =>
			{
				options.Authority = Configuration.Get<string>("AzureAd:Authority");
				options.ClientId = Configuration.Get<string>("AzureAd:ClientId");
				options.AutomaticAuthenticate = true;
				options.AutomaticChallenge = true;
				options.SignInScheme = CookieAuthenticationDefaults.AuthenticationScheme;
			});

			app.UseMvc();
        }

        public static void Main(string[] args) => WebApplication.Run<Startup>(args);
    }

ValuesController

	[Route("api/[controller]")]
	[Authorize("IsDeveloper")]
    public class ValuesController : Controller
    {
        [HttpGet]
        public IEnumerable<string> Get()
        {
            return new string[] { "value1", "value2" };
        }
    }