Mail System Error - Returned Mail

Your message was undeliverable due to the following reason:

Your message was not delivered because the destination server was not reachable within the allowed queue period. The amount of time a message is queued before it is returned depends on local configuration  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 2 days: Mail server 12.87.145.209 is not responding.

The following recipients did not receive this message:
<haproxy#formilux.org>

Please reply to postmaster#formilux.org
if you feel this message to be in error.