Problema con i servizi di identità, usermanager

InvalidOperationException: impossibile risolvere il servizio per il tipo "Microsoft.AspNetCore.Identity.UserManager`1 [MyWebsite.Models.User]" durante il tentativo di attivare "MyWebsite.Controllers.AccountController".

Ottengo questo errore quando accedo a / Account / Register

services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(
                    Configuration.GetConnectionString("DefaultConnection")));
            services.AddDefaultIdentity<IdentityUser>()
                .AddDefaultUI(UIFramework.Bootstrap4)
                .AddEntityFrameworkStores<ApplicationDbContext>();

            //services.AddIdentity<User, IdentityRole>()
            //.AddEntityFrameworkStores<ApplicationDbContext>();0

ApplicationDbContext

public class ApplicationDbContext : IdentityDbContext<User>
    {
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
            : base(options)
        {
            Database.EnsureCreated();
        }
    }

Utente di classe

public class User : IdentityUser
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Address { get; set; }
    }

Account Controller

private readonly UserManager<User> _userManager;
        private readonly SignInManager<User> _signInManager;
        private readonly RoleManager<IdentityRole> _roleManager;

        public AccountController(UserManager<User> userManager, SignInManager<User> signInManager, RoleManager<IdentityRole> roleManager)
        {
            _userManager = userManager;
            _signInManager = signInManager;
            _roleManager = roleManager;
        }

Sono nuovo, aiuto