Event not fired or not listened?

Hi all, I'm getting a strange behaviour of the events manager that doesn't fire my event. That's my controller:

public function generatePdfAction($id = null)
{
    $this->view->disable();
    $eventsManager=$this->di->get('eventsmanager');

    if($id) $params['id'] = $id;
    else throw new Exception("Error Processing Request. Confirm ID needed", 1);
    $eventsManager->fire("confirm:genPdf", $params);
    //debug
     die('stop debug');

    $responses = $eventsManager->getResponses();
    echo json_encode($responses);
}

That's the plugin listener

       use Phalcon\Events\Event;
       use Phalcon\Mvc\User\Plugin;
       use Phalcon\Di;
       use Phalcon\Di\FactoryDefault;

       class ConfirmEventQueue extends Plugin
        {
            protected $di, $queue, $logger;
            public function _construct(){
            $this->di = \Phalcon\DI::getDefault();
            $this->queue = $this->di->getQueue();
            $formatter = new \Phalcon\Logger\Formatter\Line("[".date("Y-m-d H:i:s")."][" . HOSTNAME . "][%type%] %message%");
            $this->logger = new \Phalcon\Logger\Adapter\File(LOG_PATH . "confirm/" . date('Y-m-d') . ".log");
            $this->logger->setFormatter($formatter);
            $this->logger->info("### ConfirmEventQueue ###");
           //debug line
            echo 'eventmanger';
          }
          .....
          public function genPdf(Event $event, $params = null)
          {
            //debug line
            echo "putted";
            $this->queue->putInTube('genPdf',$params);
          }
         .....

        }

This is how I attach the plugin as listener inside the Module startup:

       $di->get('eventsmanager')->attach(
           "confirm",
           new \App\Frontend\Plugins\ConfirmEventQueue()
       );

The plugin is attached because it writes the log line 'eventmanger', but it seems not to fire confirm:genPdf event because "putted" is not printed. Anyone has got an idea of what I'm doing wrong?