Apex domains cannot have CNAME records.
Question and response
Question
dig mrnetgroup.com. NS
Answer
mrnetgroup.com. 5 NS ns.mrnetgroup.com.
mrnetgroup.com. 5 NS pdns02.domaincontrol.com.
Authority
The response has no authority records.
Additional
ns.mrnetgroup.com. 5 A 92.205.233.126
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0