发送电子邮件与swiftmailer在symfony

我正在symfony中开发应用程序。我用swiftmailer发邮件。但是邮件没有收到。我不知道我错在哪里。下面是我的代码:

$message = 'Swift_Message::newInstance()
                    ->setSubject('Password Reset')
                    ->setFrom('support@bwcmultimedia.com')
                    ->setTo('karank@ocodewire.com')
                    ->setBody($this->renderView('DRPRegistrarGeneralBundle:Email:k.txt.twig'));
                $mailStatus = $this->get('mailer')->send($message);

我已经设置了参数。yml文件:

 database_driver: pdo_mysql
    database_host: 127.0.0.1
    database_port: null
    database_name: database
    database_user: user
    database_password: pass
    mailer_transport: smtp
    mailer_encryption: 
    mailer_auth_mode: "login"
    mailer_host: smtp.gmail.com
    mailer_port: 25
    mailer_user: karansofat89@gmail.com
    mailer_password: pass
    locale: en
    secret: ThisTokenIsNotSoSecretChangeIt

swiftmailer:
    transport: %mailer_transport%
    encryption: tls
    auth_mode: login
    host:      %mailer_host%
    username:  %mailer_user%
    password:  %mailer_password%

请帮