mx.myregisteredsite.com has no CNAME records.
Question and response
Question
dig mx.myregisteredsite.com. NS
Answer
The response has no answer records.
Authority
myregisteredsite.com. 20 SOA 1.ns.web.com. hostmaster.myregisteredsite.com. 2026011300 300 300 300 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0