mx2.netnames.net has no CNAME records.
Question and response
Question
dig mx2.netnames.net. NS
Answer
The response has no answer records.
Authority
netnames.net. 4523 SOA udns1.cscdns.net. hostmaster.cscdns.net. 2017101447 3600 1800 3600000 172800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0