exchange-mx.netnames.com has no MX records.
Question and response
Question
dig exchange-mx.netnames.com. MX
Answer
The response has no answer records.
Authority
netnames.com. 21600 SOA udns1.cscdns.net. hostmaster.cscdns.net. 2017101355 3600 1800 3600000 21600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0