Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace testcore
{
    public class Startup
    {
        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.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
            services.AddScoped<gameModel.gameModel>(); //don`t know y i added this
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
            services.AddAuthentication();
            services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
               .AddCookie(options => //CookieAuthenticationOptions
                {
                   options.LoginPath = new PathString("/home/Login");
               });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
                app.UseHsts();
            }
            app.UseAuthentication(); /* auth won`t work without this */  /*Obvious, but i get it after hours*/
            app.UseHttpsRedirection();
            app.UseStaticFiles();               //for ajax?
            app.UseDefaultFiles();              //for ajax?
            app.UseCookiePolicy();
            
            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Characters}/{action=Index}/");
            });
        }
    }
}