How to resolve ServiceLifetime net core lambda expression conversion error?

I am starting a very simple project with net core 2.2 and faced with the following error:
cannot convert lambda expression to type "ServiceLifetime" because it is not a delegate type

Startup file.cs

public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<CookiePolicyOptions>(options =>
            {
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });

            services.AddDbContext<Menu>(options =>
                    options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
        }

Model:

public class Menu
    {
        public int MenuID { get; set; }
        public string NmMenu {get; set;}
        public int MenuIdPai { get; set; }

    }

Context:

public class Ctx: DbContext
    {
        public Ctx(DbContextOptions<Ctx> options)
            : base(options)
        { }

        public DbSet<Menu> Menus { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Menu>().ToTable("Menu");
        }
    }

Appsettings:

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=Ctx;Trusted_Connection=True;MultipleActiveResultSets=true"
  },
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Warning"
    }
  }
}