mx.wavemail.com has no CNAME records.
Question and response
Question
dig mx.wavemail.com. NS
Answer
The response has no answer records.
Authority
wavemail.com. 894 SOA ns1.wavedns.net. dnsadmin.wavebroadband.com. 2025060600 28800 7200 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0