title: Laravel pusher Illuminate \ Broadcasting \ BroadcastException No message
body: <p>I'am using Laravel 5.5 with pusher to make a real time notification , the notification made from the Api<br>
  after i made the configuration<br>
  in the Api</p>
  
  <pre><code>     public function store(Request $request)
      { 
           $advertising = Advertising::create($request-&gt;all()); 
           $admins = \App\Admin::all();
          \Notification::send( $admins, new \App\Notifications\AdvertisingAdded($advertising) );
  
           return $advertising;
      } 
  </code></pre>
  
  <p>in AdvertisingAdded</p>
  
  <pre><code>namespace App\Notifications;
  
  use Illuminate\Bus\Queueable;
  use Illuminate\Notifications\Notification;
  use Illuminate\Contracts\Queue\ShouldQueue;
  use Illuminate\Notifications\Messages\MailMessage;
  
  use Illuminate\Notifications\Messages\BroadcastMessage;
  use App\Advertising;
  
  class AdvertisingAdded extends Notification
  {
      use Queueable;
  
      //-must be public fir pusher
      public $advertising;
  
      public function __construct(Advertising $advertising)
      {
          $this-&gt;advertising = $advertising;
      }
  
  
      public function via($notifiable)
      {
          return ['database','broadcast'];
      }
  
  
      public function toArray($notifiable)
      {
          return [
              'msg' =&gt; 'Advertising '.$this-&gt;advertising-&gt;title_ar.' is added ',
              'advertising_id' =&gt; $this-&gt;advertising-&gt;id
          ];
      }
  
      public function toBroadcast($notifiable)
      {
          return new BroadcastMessage([
              'msg' =&gt; 'Advertising '.$this-&gt;advertising-&gt;title_ar.' is added ',
              'advertising_id' =&gt; $this-&gt;advertising-&gt;id
          ]);
      }
  }
  </code></pre>
  
  <p>when i post from postman i get an error </p>
  
  <blockquote>
    <p>Illuminate \ Broadcasting \ BroadcastException No message
    <a href="https://i.stack.imgur.com/LU4k0.png" rel="noreferrer">error image</a></p>
  </blockquote>
  
  <p>i followed this video <a href="https://www.youtube.com/watch?v=i6Rdkv-DLwk" rel="noreferrer">https://www.youtube.com/watch?v=i6Rdkv-DLwk</a></p>