Issue: Zend_Mail_Protocol_Exception: cannot connect to host

#0
/library/Zend/Mail/Storage/Imap.php(273): Zend_Mail_Protocol_Imap->connect('mail.......', 143, false)
#1
/library/XenForo/Model/EmailBounce.php(304): Zend_Mail_Storage_Imap->__construct(Array)
#2
/library/XenForo/Deferred/EmailBounce.php(19): XenForo_Model_EmailBounce->openBounceHandlerConnection()
#3
/library/XenForo/Model/Deferred.php(295): XenForo_Deferred_EmailBounce->execute(Array, Array, 7.85950088501, '')
#4
/library/XenForo/Model/Deferred.php(429): XenForo_Model_Deferred->runDeferred(Array, 7.85950088501, '', false)
#5
/library/XenForo/Model/Deferred.php(374): XenForo_Model_Deferred->_runInternal(Array, NULL, '', false)
#6
/deferred.php(23): XenForo_Model_Deferred->run(false)
#7 {main}