Laravel Broadcast Private Channel doesnt work

I'm trying to do some real-time push notifications using Laravel WebSockets as a socket server and Laravel Echo with Events.

When I'm doing it on Channel, it is working fine, but now I want it to send it to private channel.

Channel('reservation.' . $this->random_key);

to

PrivateChannel('reservation.' . $this->random_key);

NewReservationEvent.php

<?php

namespace App\Events;

use Illuminate\Broadcasting\InteractsWithSockets;
use Illuminate\Broadcasting\PrivateChannel;
use Illuminate\Contracts\Broadcasting\ShouldBroadcast;
use Illuminate\Foundation\Events\Dispatchable;
use Illuminate\Queue\SerializesModels;

class NewReservationEvent implements ShouldBroadcast
{
    use Dispatchable, InteractsWithSockets, SerializesModels;

    public $message;
    public $random_key;

    /**
     * Create a new event instance.
     *
     * @return void
     */
    public function __construct($message, $user)
    {
        $this->message = $message;
        $this->random_key = $user->random_key;
    }

    /**
     * Get the channels the event should broadcast on.
     *
     * @return \Illuminate\Broadcasting\Channel|array
     */
    public function broadcastOn()
    {
        return new PrivateChannel('reservation.' . $this->random_key);
    }

    public function broadcastAs()
    {
        return 'reservation.event';
    }
}

routes/channels.php

<?php

use Illuminate\Support\Facades\Broadcast;

/*
|--------------------------------------------------------------------------
| Broadcast Channels
|--------------------------------------------------------------------------
|
| Here you may register all of the event broadcasting channels that your
| application supports. The given channel authorization callbacks are
| used to check if an authenticated user can listen to the channel.
|
*/

Broadcast::channel('App.Models.User.{id}', function ($user, $id) {
    return (int) $user->id === (int) $id;
});

Broadcast::channel('reservation.{random_key}', function ($user, $random_key){
    return true;
});

routes/web.php

Route::get('/sendEvent', function () {
    $superAdmins = User::where('role', 'Super')->get();

    foreach ($superAdmins as $superAdmin) {
        $message = 'Reservation added by';
        event(new NewReservationEvent($message, $superAdmin));
    }
});

BroadcastServiceProvider.php

<?php

namespace App\Providers;

use Illuminate\Support\Facades\Broadcast;
use Illuminate\Support\ServiceProvider;

class BroadcastServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        Broadcast::routes(['middleware' => ['auth', 'checkRole:Super,Admin,Customer']]);

        require base_path('routes/channels.php');
    }
}

And here is the Echo on my view:

Echo.private('reservation.{{ auth()->user()->random_key }}')
    .listen('.reservation.event', (e) => {
        console.log(e.message);

        $("#refreshThisDropdown").load(window.location.href + " #refreshThisDropdown");
        $("#refreshThisDropdown").load(" #refreshThisDropdown > *");

        toastr.success(e.message, "Hello there");
    })

It all works fine on Channel mode, I want to make it private just for more security.