(Un?sent?) eMail being returned

I use the old 7.1.0.9 Eudora with much joy. However, occasionally strange things happen . Now it is :MAILER-DAEMON@mail.gmx.com" , hundreds of bounced emails saying "A message that you sent could not be delivered to one or more of
its recipients. This is a permanent error. The following address
failed:" I note other threads similar. All I ask is you read the attached email image and see if you can sniff out what is causing the problem. In every case the addresse is valid.

it is my regular RR email address, no problem. But the message says I sent the email, and even tho the addressor might be one I have received before, I did not recently send them anything. For example:

"Received: from mta2.mail.advantagebusinessmedia.com ([<snip>]) by
mx-ha.gmx.net (mxgmxus003) with ESMTP (Nemesis) id 0MY7AE-1VCSla1L8q-00UpxF
for <jhebbard@techxxxxxt.com>; Mon, 21 Oct 2013 21:31:34 +0200"

My redaction is because of fear of spam. Note the "for" address is my mail.com forwarding account. I suspicion RR may be rejecting because of spam, but this is peculiar. And mail.com is showing nothing in spam. Is there someone trustworthy (a major geek) that I can send a text copy of the bounce message for a few minutes debugging?
I am at sea with this one.

Thanks! =>Jim<= Enginer

 

Jim,

I have removed identifying information from this thread. We try to avoid leaving that for the Internet to see as it can and will cause you problems.

 

Most likely your email address has been misused by a spammer, who forged it into the 'From:' address. Hence the bounces go to you.

If you get the full headers of the original spam messages, you can easily determine from where (IP address) the original messages have been sent.