title: Laravel 5.5 BroadcastException with Pusher
body: <p>I have create the chat application in laravel with Brodecast+Vue so when trying to my test broadcast class its getting error <strong>"BroadcastException in PusherBroadcaster.php (line 106)"</strong> I have double checked all configurations and api authentications are correct. but getting error and pusher debug console do not display and request. </p>
  
  <p>driver : </p>
  
  <pre><code>'pusher' =&gt; [
          'driver' =&gt; 'pusher',
          'key' =&gt; env('PUSHER_APP_KEY'),
          'secret' =&gt; env('PUSHER_APP_SECRET'),
          'app_id' =&gt; env('PUSHER_APP_ID'),
          'options' =&gt; [
              'cluster' =&gt; 'ap1',
              'encrypted' =&gt; true
          ],
      ],
  </code></pre>
  
  <p>event :</p>
  
  <pre><code>public $message;
  public $user;
  
  public function __construct($message, User $user)
  {
      $this-&gt;message = $message;
      $this-&gt;user = $user;
  }
  </code></pre>
  
  <p>test function :</p>
  
  <pre><code>public function test()
  {
      $user = User::find(Auth::id());
      event(new ChatEvent('Hello pusher', $user));
      return response('done');
  }
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/nxFI0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nxFI0.png" alt="screen shot"></a></p>