mx.eonix.net has no CNAME records.
Question and response
Question
dig mx.eonix.net. NS
Answer
The response has no answer records.
Authority
eonix.net. 1791 SOA anirban.ns.cloudflare.com. dns.cloudflare.com. 2397325578 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0