The message was undeliverable due to the following reason(s): Your message could not be delivered because the destination computer was not reachable within the allowed queue period. The amount of time a message is queued before it is returned depends on local configura- tion parameters. Most likely there is a network problem that prevented delivery, but it is also possible that the computer is turned off, or does not have a mail system running right now. Your message could not be delivered within 3 days: Host 18.104.22.168 is not responding. The following recipients could not receive this message: <email@example.com> Please reply to firstname.lastname@example.org if you feel this message to be in error.