Could not read from mail.xxxxx.com

What does it means ? and how i can solve it ? 

Thanks

  'transport' => 'Zend\Mail\Transport\Smtp',
        'transport_options' => array(
            'host' => 'mail.liveonly.com',
            'connection_class' => 'login',
            'connection_config' => array(
                'username' => 'aaaa',
                'password' => 'xxxx',
            ),
        ),
