From: The Post Office <postmaster>
Sender:	mailer-daemon
Subject: Invalid host/domain name
Cc: The Post Office <postoffice>

In the following message, it appears from the format of certain addresses
that you were trying to submit an article to a USENET newsgroup.
Unfortunately, the newsgroup names could not be found in our list of
active newsgroups (kept in /local/share/mail/db/active, for your reference).

