How to specify endpoint to auth Pusher in Laravel?

I use this authentication rule before sending private message using Pusher:

Broadcast::channel('order.*', function ($user, Order $order) {
    return $order->getAttributeValue("User_Id") === $user->id;
});

My local address where is placed Laravel is:

http://127.0.0.1:8000/

On this local machine also there is client JS (Pusher) that listens messages:

 var pusher = new Pusher('8976a4ebddd8b0fe2a555', {
     authEndpoint: 'http://127.0.0.1:8000/',
      cluster: 'eu',
      forceTLS: true
    });

How to specify correct endpoint address on client to receive private message?

As you can see I tried:

 authEndpoint: 'http://127.0.0.1:8000/',

via Chebli Mohamed