_userManager.GeneratePasswordResetTokenAsync(user); NotSupportedException No IUserTwoFactorTokenProvider<TUser> named 'Default' is registered 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!
// ....
}