THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
...
If the domain name in the message ID does not match the domain name in the From: header, the message may hit the SpamAssassin 'MID_ADDED_BY_RELAY' rules, and therefore may cause a false positive.
This is a bug in Outlook Express, and there is no known workaround. For further details:
\[ Wiki Markup
http://bugzilla.spamassassin.org/show_bug.cgi?id=2072\]
Update: Mar 2007: the rule is no longer part of SA, removed some time before 3.2.0.
...