Redis – Laravel broadcastOn() method in event never fires

I am new to laravel and to websockets. I have got my websockets working on the laravel-websockets dashboard, and now am trying to trigger a websocket event with this javascript command:

axios.post('updatequeue', {queue_position: newPos});

newPos is a number.

This is my controller method:

public function updateQueue(Request $request){
        $queueposition = $request->input('queue_position');
        event(new QueueUpdate($queueposition));
}

This is my Event:

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

    public $queue_position;

    /**
     * Create a new event instance.
     *
     * @return void
     */
    public function __construct($queue_position)
    {
        $this->queue_position = $queue_position;

    }

    /**
     * Get the channels the event should broadcast on.
     *
     * @return IlluminateBroadcastingChannel|array
     */
    public function broadcastOn()
    {
        return new Channel('sessionid');
    }
}

When I watch for events in the dashboard, nothing shows up. I get a 200 response from the axios request. I have placed logs throughout, and my events __construct method is called, but broadcastOn() is not.
I am really stuck here, if anyone has any ideas, I would be very grateful.

EDIT

here is my broadcasting.php:

<?php

return [

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

    'connections' => [

        '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'),
                'host'          => env('WEBSOCKET_BROADCAST_HOST'),
                'port'          => env('WEBSOCKET_BROADCAST_PORT'),
                'scheme'        => env('WEBSOCKET_SCHEME'),
                'encrypted'     => env('WEBSOCKET_ENCRYPTED'),
            ],
        ],

        'redis' => [
            'driver' => 'redis',
            'connection' => 'default',
        ],

        'log' => [
            'driver' => 'log',
        ],

        'null' => [
            'driver' => 'null',
        ],

    ],

];

and websockets.php:

<?php

use BeyondCodeLaravelWebSocketsDashboardHttpMiddlewareAuthorize;

return [


    'dashboard' => [
        'port' => env('LARAVEL_WEBSOCKETS_PORT', 6001),
    ],

    'apps' => [
        [
            'id' => env('PUSHER_APP_ID'),
            'name' => env('APP_NAME'),
            'key' => env('PUSHER_APP_KEY'),
            'secret' => env('PUSHER_APP_SECRET'),
            'enable_client_messages' => false,
            'enable_statistics' => true,
        ],
    ],

    'app_provider' => BeyondCodeLaravelWebSocketsAppsConfigAppProvider::class,


    'allowed_origins' => [
        //
    ],

    'max_request_size_in_kb' => 250,

    'path' => 'laravel-websockets',

    'middleware' => [
        'web',
        Authorize::class,
    ],

    'statistics' => [

        'model' => BeyondCodeLaravelWebSocketsStatisticsModelsWebSocketsStatisticsEntry::class,

        'interval_in_seconds' => 60,


        'delete_statistics_older_than_days' => 60,

        'perform_dns_lookup' => false,
    ],


    'ssl' => [

        'local_cert' => env('LARAVEL_WEBSOCKETS_SSL_LOCAL_CERT', null),

        'local_pk' => env('LARAVEL_WEBSOCKETS_SSL_LOCAL_PK', null),

        'passphrase' => env('LARAVEL_WEBSOCKETS_SSL_PASSPHRASE', null),

        'verify_peer' => env('LARAVEL_WEBSOCKETS_SSL_VERIFY_PEER', true),
    ],


    'channel_manager' => BeyondCodeLaravelWebSocketsWebSocketsChannelsChannelManagersArrayChannelManager::class,
];

EDIT

I am local.
Here are the values for broadcasting.php:

'driver' => 'pusher',
            'key' => portalkey,
            'secret' => secret,
            'app_id' => portalID,
                'cluster'       => portalcluster,
                'host'          => 127.0.0.1,
                'port'          => 6001,
                'scheme'        => http,
                'encrypted'     => false,