Уведомление Laravel - вызов функции-члена routeNotificationFor () в строке

Laravel 5.5

Контроллер

public function sendBookingSms(){
  $checkState = session()->get('checkState');
  $staffs = Staff::whereIn('staffId',$checkState)->get();
  foreach ($staffs as $staff) {
    $email = str_replace(" ","","44".substr($staff->mobile, 1)).'@mail.mightytext.net';
    Notification::send($email, new NewBooking($email));
  }
  return $staffs;
  session()->forget('checkState');
  return redirect(route('booking.current'))->with('message','Succesfully Send SMS to selected staffs !!');
}

NewBooking.php (Уведомление)

public function toMail($notifiable)
{
    return (new MailMessage)
                ->line('The introduction to the notification.')
                ->action('Notification Action', url('/'))
                ->line('Thank you for using our application!');
}

При вызове этого контроллера я получаю эту ошибку.

$ посохи.

{  
   "staffId":45,
   "forname":"Eldhose",
   "surname":"John",
   "categoryId":2,
   "email":"[email protected]",
   "mobile":"07588593278",
   "whatsappNumber":"57656578658",
   "gender":1,
   "address":"Poole",
   "pincode":null,
   "modeOfTransport":1,
   "pickupLocation":"Office",
   "branchId":0,
   "zoneId":1,
   "bandId":1,
   "paymentMode":1,
   "payRateWeekday":10,
   "payRateWeekNight":20,
   "payRateWeekendDay":10,
   "payRateWeekendNight":20,
   "payRateSpecialBhday":11,
   "payRateSpecialBhnight":15,
   "payRateBhday":11,
   "payRateBhnight":15,
   "status":1,
   "deleted_at":null,
   "created_at":"2018-02-26 22:16:44",
   "updated_at":"2018-02-26 22:16:44"
}

Пожалуйста, помогите мне в этом .... Спасибо