Laravel Reverb, App key {key} not in this cluster.

Hello,

I've currently stuck on an issue. Where I have an event that is setup to broadcast, however I am getting the following error when Horizon tries to process the event to broadcast.

Illuminate\Broadcasting\BroadcastException: Pusher error: App key {key} not in this cluster. Did you forget to specify the cluster?

I am currently setting this up on my local, using Laravel Sail. The only configuration I've made to Laravel Sail is adding this to the port of the server I am running Reverb on

- '${REVERB_SERVER_PORT:-8080}:8080'

My assumption is Reverb uses Pushers Libaries in order to push the Event & it's potentially having some cross-over. But I could be wrong. My Event class is setup like this

<?php

namespace App\Events;

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

final class SetToPending implements ShouldBroadcast, ShouldDispatchAfterCommit
{
    use Dispatchable;
    use SerializesModels;

And of-course this is how I've setup my broadcasting config files.

<?php

return [

    /*
    |--------------------------------------------------------------------------
    | Default Broadcaster
    |--------------------------------------------------------------------------
    |
    | This option controls the default broadcaster that will be used by the
    | framework when an event needs to be broadcast. You may set this to
    | any of the connections defined in the "connections" array below.
    |
    | Supported: "pusher", "ably", "redis", "log", "null"
    |
    */

    'default' => env('BROADCAST_DRIVER', 'reverb'),

    /*
    |--------------------------------------------------------------------------
    | Broadcast Connections
    |--------------------------------------------------------------------------
    |
    | Here you may define all of the broadcast connections that will be used
    | to broadcast events to other systems or over websockets. Samples of
    | each available type of connection are provided inside this array.
    |
    */

    'connections' => [
        'reverb' => [
            'driver' => 'reverb',
            'app_id' => env('REVERB_APP_ID'),
            'key' => env('REVERB_APP_KEY'),
            'secret' => env('REVERB_APP_SECRET'),
            'app_name' => env('REVERB_APP_NAME', 'reverb-app'),
            'host' => env('REVERB_HOST', '127.0.0.1'),
            'port' => env('REVERB_PORT', 8080),
            'scheme' => env('REVERB_SCHEME', 'http'),
        ],
    ],
];

Whilst the reverb config file is setup like the following.

<?php

return [

    /*
    |--------------------------------------------------------------------------
    | Default Reverb Server
    |--------------------------------------------------------------------------
    |
    | This option controls the default server used by Reverb to handle
    | incoming messages as well as broadcasting message to all your
    | connected clients. At this time only "reverb" is supported.
    |
    */

    'default' => env('REVERB_SERVER', 'reverb'),

    /*
    |--------------------------------------------------------------------------
    | Reverb Servers
    |--------------------------------------------------------------------------
    |
    | Here you may define details for each of the supported Reverb servers.
    | Each server has its own configuration options that are defined in
    | the array below. You should ensure all the options are present.
    |
    */

    'servers' => [

        'reverb' => [
            'host' => env('REVERB_SERVER_HOST', '0.0.0.0'),
            'port' => env('REVERB_SERVER_PORT', 8080),
            'hostname' => env('REVERB_HOST'),
            'options' => [
                'tls' => [],
            ],
            'max_request_size' => env('REVERB_MAX_REQUEST_SIZE', 10_000),
            'scaling' => [
                'enabled' => env('REVERB_SCALING_ENABLED', false),
                'channel' => env('REVERB_SCALING_CHANNEL', 'reverb'),
                'server' => [
                    'url' => env('REDIS_URL'),
                    'host' => env('REDIS_HOST', '127.0.0.1'),
                    'port' => env('REDIS_PORT', '6379'),
                    'username' => env('REDIS_USERNAME'),
                    'password' => env('REDIS_PASSWORD'),
                    'database' => env('REDIS_DB', '0'),
                ],
            ],
            'pulse_ingest_interval' => env('REVERB_PULSE_INGEST_INTERVAL', 15),
            'telescope_ingest_interval' => env('REVERB_TELESCOPE_INGEST_INTERVAL', 15),
        ],

    ],

    /*
    |--------------------------------------------------------------------------
    | Reverb Applications
    |--------------------------------------------------------------------------
    |
    | Here you may define how Reverb applications are managed. If you choose
    | to use the "config" provider, you may define an array of apps which
    | your server will support, including their connection credentials.
    |
    */

    'apps' => [

        'provider' => 'config',

        'apps' => [
            [
                'key' => env('REVERB_APP_KEY'),
                'secret' => env('REVERB_APP_SECRET'),
                'app_id' => env('REVERB_APP_ID'),
                'options' => [
                    'host' => env('REVERB_HOST'),
                    'port' => env('REVERB_PORT', 443),
                    'scheme' => env('REVERB_SCHEME', 'https'),
                    'useTLS' => env('REVERB_SCHEME', 'https') === 'https',
                ],
                'allowed_origins' => ['*'],
                'ping_interval' => env('REVERB_APP_PING_INTERVAL', 60),
                'max_message_size' => env('REVERB_APP_MAX_MESSAGE_SIZE', 10_000),
            ],
        ],
    ],
];

Just for consolation, the frontend Laravel Echo libaray is successfull connected & authenticated to the correct Private channel.