this is what i saw in system log :
IPS\Email\Incoming\PopImapException::0
pop3_login_err
BACKTRACE
#0 /var/www/mydomain.com/public_html/v1/applications/core/tasks/pop.php(50): IPS\Email\Incoming\_PopImap->__construct()
#1 /var/www/mydomain.com/public_html/v1/system/Task/Task.php(281): IPS\core\tasks\_pop->execute()
#2 /var/www/mydomain.com/public_html/v1/system/Task/Task.php(244): IPS\_Task->run()
#3 /var/www/mydomain.com/public_html/v1/applications/core/interface/task/task.php(72): IPS\_Task->runAndLog()
#4 {main}