So this is weird and I'm not quite sure how to resolve it...

We had a user, but then deleted it and instead made it an alias for another account.

However now when you send it a message it bounces:

<X@X.com>: x.com
Reporting-MTA: dns; mail.ourdomain.com
Original-Envelope-Id: 0MKO00GNRVGW2QB0@st11p01mm-asmtp001.mac.com
X-Postfix-Queue-ID: 5BFAB7228206
X-Postfix-Sender: rfc822; test@mac.com
Arrival-Date: Wed, 3 Apr 2013 10:05:53 -0700 (PDT)

Final-Recipient: rfc822; x@x.com
Original-Recipient: rfc822;x@x.com
Action: failed
Status: 5.0.0
Diagnostic-Code: X-Postfix; x.com


BUT the message IS delivered to the address which this account is an alias for.

Any ideas?