mx2.smartape.net has no CNAME records.
Question and response
Question
dig mx2.smartape.net. NS
Answer
The response has no answer records.
Authority
smartape.net. 2133 SOA ns3.smartape.net. abuse.smartape.net. 2013041697 3600 7200 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0