php - Symfony 2 emails very slowly with google's transport -

in our production server facing unexpected problem.

from yesterday requests imply sending emails take long time. of requests finish @ end of second minute, of them terminates exception:

[2015-07-10 15:40:18] request.critical: uncaught php exception swift_transportexception: "expected response code 250 got code "", message """ @ /var/www/html/project/vendor/swiftmailer/swiftmailer/lib/classes/swift/transport/abstractsmtptransport.php line 386 {"exception":"[object] (swift_transportexception: expected response code 250 got code \"\", message \"\" @ /var/www/html/project/vendor/swiftmailer/swiftmailer/lib/classes/swift/transport/abstractsmtptransport.php:386)"} [] 

configuration ordinar:

mailer_transport: gmail mailer_username: *** mailer_user: *** mailer_password: *** mailer_from: *** 

sending also:

$message = \swift_message::newinstance()     ->setsubject('confirmation')     ->setfrom($this->container->getparameter('mailer_from'))     ->setto($email)     ->setbody($this->renderview('bundle:emails:emailconfirmation.html.twig',  array('invoice' => $invoice)), 'text/html'); $mailer->send($message); 

pay attention works fine takes 2 mins brakes.

other symptom when starting emailing ever it's not possible request site same browser (it waits). whereas other browser loads site usual.

it's not depend on email volume. tiny emails of password reinit can cause that.

any ideas ?

thanks.