Error 404

Olá, Saulo!
Tudo bem?

Registrou as rotas no arquivo web.php?
Broadcast::routes();

Limpa o cache também:
php artisan route:cache

Olá!

SIm esta definido

<?php

namespace App\Providers;

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

class BroadcastServiceProvider extends ServiceProvider
{
 
    public function boot()
    {
        Broadcast::routes();

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

Repositorio do projeto

https://github.com/saulo1212/laravel_notifications.git

Olá, Saulo!

Pulou uma etapa do curso, faltou declarar o Provider BroadcastServiceProvider no arquivo de configuração config/app.php

Para isso precisa remover o comentário dessa linha:
// App\Providers\BroadcastServiceProvider::class,

Ola!

Ja esta descomentado o provider

'providers' => [

    /*
     * Laravel Framework Service Providers...
     */
    Illuminate\Auth\AuthServiceProvider::class,
    Illuminate\Broadcasting\BroadcastServiceProvider::class,
    Illuminate\Bus\BusServiceProvider::class,
    Illuminate\Cache\CacheServiceProvider::class,
    Illuminate\Foundation\Providers\ConsoleSupportServiceProvider::class,
    Illuminate\Cookie\CookieServiceProvider::class,
    Illuminate\Database\DatabaseServiceProvider::class,
    Illuminate\Encryption\EncryptionServiceProvider::class,
    Illuminate\Filesystem\FilesystemServiceProvider::class,
    Illuminate\Foundation\Providers\FoundationServiceProvider::class,
    Illuminate\Hashing\HashServiceProvider::class,
    Illuminate\Mail\MailServiceProvider::class,
    Illuminate\Notifications\NotificationServiceProvider::class,
    Illuminate\Pagination\PaginationServiceProvider::class,
    Illuminate\Pipeline\PipelineServiceProvider::class,
    Illuminate\Queue\QueueServiceProvider::class,
    Illuminate\Redis\RedisServiceProvider::class,
    Illuminate\Auth\Passwords\PasswordResetServiceProvider::class,
    Illuminate\Session\SessionServiceProvider::class,
    Illuminate\Translation\TranslationServiceProvider::class,
    Illuminate\Validation\ValidationServiceProvider::class,
    Illuminate\View\ViewServiceProvider::class,

    /*
     * Package Service Providers...
     */

    /*
     * Application Service Providers...
     */
    App\Providers\AppServiceProvider::class,
    App\Providers\AuthServiceProvider::class,
    App\Providers\BroadcastServiceProvider::class,
    App\Providers\EventServiceProvider::class,
    App\Providers\RouteServiceProvider::class,

],

Então o seu projeto no GitHub está desatualizado... \_(ツ)_/

https://github.com/saulo1212/laravel_notifications.git

Ola!

Tudo joia?

Subi com a correção

https://github.com/saulo1212/laravel_notifications

ainda continuo com o erro 404 

http://localhost/broadcasting/auth

Olá amigo!
Tudo joia.

Se persistir os erros vou precisar baixar e rodar o seu projeto, para identificar onde errou.

Essa rota existe?
php artisan route:list

(print: https://imgur.com/upload)

---------

Limpa as configurações de cache também:
php artisan cache:clear
php artisan route:cache  
php artisan config:clear
php artisan view:clear

Ola!

php artisan route:list

GET|POST|HEAD | broadcasting/auth      |                  | Illuminate\Broadcasting\BroadcastController@authenticate               | web          |

ja fiz tambem a parte de limpeza das configurações, não resolveu

Olá, Saulo!

Envia um e-mail para [email protected] (com o número do chamado 1340) que vamos combinar um horário para eu acessar o seu projeto e te ajudar a encontrar o problema.

No aguardo.