84. Notificaciones en tiempo real

Estoy tratando de implementar este paso connjuntamente con las notificaciones via 

broadcast pero estoy teniendo este error y no se que es
me puede ayudar?

Illuminate\Broadcasting\BroadcastException in /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Broadcasting/Broadcasters/PusherBroadcaster.php:117

Stack trace:

#0 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Broadcasting/BroadcastEvent.php(49): Illuminate\Broadcasting\Broadcasters\PusherBroadcaster->broadcast(Array, 'Illuminate\\Noti...', Array)

#1 [internal function]: Illuminate\Broadcasting\BroadcastEvent->handle(Object(Illuminate\Broadcasting\Broadcasters\PusherBroadcaster))

#2 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(29): call_user_func_array(Array, Array)

#3 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(87): Illuminate\Container\BoundMethod::Illuminate\Container\{closure}()

#4 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(31): Illuminate\Container\BoundMethod::callBoundMethod(Object(Illuminate\Foundation\Application), Array, Object(Closure))

#5 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Container/Container.php(572): Illuminate\Container\BoundMethod::call(Object(Illuminate\Foundation\Application), Array, Array, NULL)

#6 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Bus/Dispatcher.php(94): Illuminate\Container\Container->call(Array)

#7 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(128): Illuminate\Bus\Dispatcher->Illuminate\Bus\{closure}(Object(Illuminate\Broadcasting\BroadcastEvent))

#8 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(104): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Broadcasting\BroadcastEvent))

#9 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Bus/Dispatcher.php(98): Illuminate\Pipeline\Pipeline->then(Object(Closure))

#10 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Queue/CallQueuedHandler.php(49): Illuminate\Bus\Dispatcher->dispatchNow(Object(Illuminate\Broadcasting\BroadcastEvent), false)

#11 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Queue/Jobs/Job.php(83): Illuminate\Queue\CallQueuedHandler->call(Object(Illuminate\Queue\Jobs\RedisJob), Array)

#12 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(327): Illuminate\Queue\Jobs\Job->fire()

#13 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(277): Illuminate\Queue\Worker->process('redis', Object(Illuminate\Queue\Jobs\RedisJob), Object(Illuminate\Queue\WorkerOptions))

#14 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(118): Illuminate\Queue\Worker->runJob(Object(Illuminate\Queue\Jobs\RedisJob), 'redis', Object(Illuminate\Queue\WorkerOptions))

#15 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Queue/Console/WorkCommand.php(102): Illuminate\Queue\Worker->daemon('redis', 'default', Object(Illuminate\Queue\WorkerOptions))

#16 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Queue/Console/WorkCommand.php(86): Illuminate\Queue\Console\WorkCommand->runWorker('redis', 'default')

#17 [internal function]: Illuminate\Queue\Console\WorkCommand->handle()

#18 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(29): call_user_func_array(Array, Array)

#19 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(87): Illuminate\Container\BoundMethod::Illuminate\Container\{closure}()

#20 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(31): Illuminate\Container\BoundMethod::callBoundMethod(Object(Illuminate\Foundation\Application), Array, Object(Closure))

#21 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Container/Container.php(572): Illuminate\Container\BoundMethod::call(Object(Illuminate\Foundation\Application), Array, Array, NULL)

#22 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Console/Command.php(183): Illuminate\Container\Container->call(Array)

#23 /var/www/html/hunterv2/vendor/symfony/console/Command/Command.php(255): Illuminate\Console\Command->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Illuminate\Console\OutputStyle))

#24 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Console/Command.php(170): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Illuminate\Console\OutputStyle))

#25 /var/www/html/hunterv2/vendor/symfony/console/Application.php(908): Illuminate\Console\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))

#26 /var/www/html/hunterv2/vendor/symfony/console/Application.php(269): Symfony\Component\Console\Application->doRunCommand(Object(Illuminate\Queue\Console\WorkCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))

#27 /var/www/html/hunterv2/vendor/symfony/console/Application.php(145): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))

#28 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Console/Application.php(89): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))

#29 /var/www/html/hunterv2/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(122): Illuminate\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))

#30 /var/www/html/hunterv2/artisan(37): Illuminate\Foundation\Console\Kernel->handle(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))

#31 {main}