Actually... I lied.

Now when i try to send an email to this user i get this back:

Your message did not reach some or all of the intended recipients.

Subject: Test
Sent: 4/4/2008 11:16 AM

The following recipient(s) cannot be reached:

<username_removed> on 4/4/2008 11:16 AM
A configuration error in the e-mail system caused the message to bounce between two servers or to be forwarded between two recipients. Contact your administrator.


Edit: From the event log:

Cause: A forward loop was detected by the categorizer. This is a common hosting configuration problem caused when someone uses the provisioning tool to create a contact in one organization unit and creates a user in a different organization user that share the same e-mail address.

Solution: Verify that you do not have a user in organizational unit and a contact in a different organizational unit that have the same e-mail address.