has.*been.*delayed|delayed *mail|message *delayed|message-expired|temporar(il)?y *(failure|unavailable|disable|offline|unable)|deferred|delayed *([0-9]*) *(hour|minut)|possible *mail *loop|too *many *hops|delivery *time *expired|Action: *delayed|status(-code)? *(:|=)? *4.4.6|will continue to be attempted|unable to deliver in.*Status: 4.4.7