Sign up using Microsoft's own newspaper NotSupportedException: No IUserTwoFactorTokenProvider <TUser> named 'Default' is registered.
Because the startup configuration file is missing
Sign up below blue background services
services.AddIdentity<ApplicationUser, IdentityRole>(options =>
{
options.Password.RequireNonAlphanumeric = false;
options.Password.RequiredLength = 1;
options.Password.RequireLowercase = false;
options.Password.RequireUppercase = false;
})
.AddDefaultUI(UIFramework.Bootstrap4)
.AddEntityFrameworkStores<ApplicationDbContext>()
.AddDefaultTokenProviders();