hello everybody I'll really appreciate your help on this as I'm trying to sent a simple email and I can not here is my config.yml

swiftmailer:
    transport: sendmail
    host:      /usr/bin/sendmail
    username:  %mailer_user%
    password:  %mailer_password%
    spool:
        type: file
        path: "%kernel.cache_dir%/swiftmailer/spool"

I see the emails keep on spool and they are never released Event after enter this command in console php app/console swiftmailer:spool:send --env=prod /*for more details here is my controller code*/

        $message = \Swift_Message::newInstance()
            //->attach($attachment)
            ->setContentType("text/html")
            ->setSubject('Hello Email')
            ->setFrom('send@example.com')
            ->setTo('schell.daniel@gmail.com')
            ->setBody(
                $this->renderView(
                    'MasEventosSICBundle:Welcome:registration.html.twig',
                    array('name' => $name)
                )
            )
        ;
        $this->get('mailer')->send($message);            

This does not throw any exception but the emails are not sent I think my knowledge is not enough to see the cause Thanks a lot in advance Cheers