mx01.active-w.net has no CNAME records.
Question and response
Question
dig mx01.active-w.net. NS
Answer
The response has no answer records.
Authority
active-w.net. 742 SOA ns-923.awsdns-51.net. awsdns-hostmaster.amazon.com. 2015081001 7200 900 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0