mail1.netnames.com has no CNAME records.
Question and response
Question
dig mail1.netnames.com. NS
Answer
The response has no answer records.
Authority
netnames.com. 222 SOA udns1.cscdns.net. hostmaster.cscdns.net. 2017101355 3600 1800 3600000 21600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0