pusher connected but when i try to add new message it's give me forbidden route

I build chat with laravel & vue js & pusher it's worked correctly but i host this project and i have this problem when a try ato add new message

/chat/ 403 (Forbidden)

This my confic in broadcasting.php

    'pusher' => [
        'driver' => 'pusher',
        'key' => env('PUSHER_APP_KEY'),
        'secret' => env('PUSHER_APP_SECRET'),
        'app_id' => env('PUSHER_APP_ID'),
        'options' => [
            'cluster' => env('PUSHER_APP_CLUSTER'),
            'encrypted' =>true,
            'useTLS'  => false,
        ],
    ],

File bootstrap.js

import Echo from 'laravel-echo';

window.Pusher = require('pusher-js');

    window.Echo = new Echo({
    broadcaster: 'pusher',
    key: process.env.MIX_PUSHER_APP_KEY,
    cluster: process.env.MIX_PUSHER_APP_CLUSTER,
    encrypted:true,
    // forceTLS: true
});

enter code here

---

This my event file source

public function broadcastOn()
{
    return new PrivateChannel('chat.'.$this->message->ticket_id);
}

public function broadcastAs()
{
    return 'new.message';
}

---

Route channel

Broadcast::channel('chat.{ticket_id}', function ($user, $ticket_id) {

    if(Auth::check()){

       return ['id'=>$user->id,'name'=>$user->name];

    }

});

---

this is my method for add new message in backend

public function store(Request $request)
{
    $success = Message::create([
        'message'         => $request->message,
        'user_id'         => $request->user_id ,
        'ticket_id'       => $request->ticket_id ,
    ]);

    broadcast(new NewChatMessage($success))->toOthers();

    if($success){
        $messages = Ticket::where('id',$request->ticket_id)
        ->with('messages',function($query){
            $query->orderBy('created_at','ASC');
            $query->with('user');
        })
        ->first();
        return $messages->messages;
    }
}

---

This my method in frontend

        addComment(id){
            if(this.messages[0]){
                this.newComment.ticket_id = this.messages[0].ticket_id
                this.newComment.user_id = id;
                axios.post('/chat',this.newComment)
                .then((res)=>{
                    this.newComment = {}
                })
                .catch(err=>console.log(err))}
             }
        },

via Chebli Mohamed