I believe this relates to a SpamCop Reporting Account Registered e-mail address being tagged as "bouncing/not available/screwed up" but not totally sure (will send out some e-mail asking for someone to explain what is/was going on) ... so This is all I know right now ....
QUOTE
From: SpamCop Admin <nobody[at]devnull.spamcop.net>
Newsgroups: spamcop
Subject: Re: Spamcop claims my address bounces
Date: Mon, 09 Jan 2006 11:39:47 -0700
Message-ID: <sqm3s1ttclvoc0tauvtc8un2bc66v4u4dv[at]4ax.com>

>-It looks like there may still be a problem as I've just had to reset the
>-bounce flag again.

It turns out that there has been an intermittent problem with the
Email Service mail servers not talking to each other, which caused the
reporting system email to bounce occasionally.

I have just been told that the problem has been fixed.  Hopefully,
that will put an end to the problem.

- Don D'Minion - SpamCop Admin -

There is a Topic 'here' that comes close to matching, but most of the folks there returned with reports of their ISPs fixing things, so not sure of the connection here ... see Your email address has returned a bounce