Email Alert didn't work when device is down - Professional Edition

Email Alert Not working when server down

1. test_mail.php working good
root@observium:/opt/observium# ./test_mail.php -h 192.168.1.3
Observium 0.15.1.6221
Test E-mail Configuration

See mail backend options here: http://www.observium.org/wiki/Configuration_Options#Email_backend_settings

My Hostname: observium.litmuse.com
E-mails ENABLED globally ($config['email']['enable'])
E-mails use PHP-builtin MAIL backend ($config['email']['backend'])
E-mails send from ($config['email']['from']):
alter@localhost
E-mails send to recipients based on default recipient from config and/or device sysContact.
Try send test notification for 192.168.1.3 to these email(s):
sebae@localhost
Notification for 192.168.1.3 SENT.
root@observium:/opt/observium#

2. system alter not working /config.php
Professional Edition(Brand new)

// Enable alerter (not available in CE)
$config['poller-wrapper']['alerter'] = TRUE;

$config['email']['enable'] = TRUE;
$config['email']['from'] = 'alter@localhost';
$config['email']['default'] = NULL;
$config['email']['default_only'] = FALSE;
$config['email']['backend'] = 'mail';

$config['alerts']['alerter']['default']['descr'] = "Default Email Alert";
$config['alerts']['alerter']['default']['type'] = "email";
$config['alerts']['alerter']['default']['contact'] = "sebae@localhost";
$config['alerts']['alerter']['default']['enable'] = TRUE;

• Attach my setting screen shot