We have received reports today of a number of customers unable to receive email, the message generated is:
501 Mail rejected because the server you are sending to is misconfigured.
The problem is caused by people using anti-spam blacklists related to the ORBZ blacklist. ORBZ was disbanded last year due to legal actions. However, many administrators have not re-configured their servers to no longer use this information. The previous ORBZ organisation has now blacklisted ALL internet IPs in its database to force people to re-configure their systems correctly.
If you have a customer experiencing this problem you will need to get them to disable the ORBZ anti-spam control which should resolve the issue.
For more information an explanation has been posted on the ORBZ website at http://www.orbz.org/
Useful link: ORB Website
