SpamCop FAQ : SpamCop Parsing and Reporting Service : Parsing and reporting spam with SpamCop - decisions, problems :
There are many possible reasons for this message. Basically, there are three main categories:

1. Problems at your end:
   The header of the spam didn't have enough information to figure out what IP the spam came from. This happens sometimes on very old or strangely configured email systems. For instance, if you are using a Novell or old Microsoft server, you may have this problem. The problem also occurs with hotmail, but only intermitantly. If this is the problem, you will probably see it with ALL email (unless you use hotmail, then only sometimes).
2. Problems at the spammer's end:
   SpamCop couldn't figure out who is responsible for the IP that the spam originated from. This is sometimes caused by temporary network outages. It can also be caused by poorly configured DNS servers and out-of-date IP registration information.
3. All issues have already been resolved:
   Sometimes you will receive this message because all hosts involved (originating IP, web/email hosts) have reported back to SpamCop action has been taken and closed the issues.

View the messages in red to find the specific reason for this message and then check the other FAQs in this category for more information on the solutions.
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