Cakephp SMTP emails syntax error

Hello, I've got a problem with email sending in cake. My method looks like this:

$this->Email->smtpOptions = array(
'port'=>'465',
'timeout'=>'30',
'auth' => true,
'host' => 'ssl://smtp.gmail.com',
'username'=>'mymail@gmail.com',
'password'=>'mypass',
);

$this->Email->from = "admin@localhost";
$this->Email->to = "my_test_mail@centrum.cz";
$this->Email->subject = "Test";
$this->Email->sendAs = "text";

$this->Email->delivery = 'smtp';

$this->Email->send('Hello message body!');

But when I try to send the email I get:

555 5.5.2 Syntax error. l3sm512374fan.0

What do I need to chnage in order for this to work?

Thanks