no iusertwofactortokenprovider tuser named 'default' is registered .net core code example

Example: No IUserTwoFactorTokenProvider named 'Default' is registered.'

// startup.cs
public void ConfigureServices(IServiceCollection services)
{
  // ....
  services.AddIdentityCore<User, UserRole>()
    .AddEntityFrameworkStores<ApplicationDbContext>()
    .AddDefaultTokenProviders(); // Remember to add this line!
  // ....
}