Apex domains cannot have CNAME records.
Question and response
Question
dig nrnet.com. NS
Answer
nrnet.com. 4 NS ns.nrnet.com.
nrnet.com. 4 NS ns.nr.net.
Authority
The response has no authority records.
Additional
ns.nr.net. 4 A 104.238.144.219
ns.nrnet.com. 4 A 104.238.144.219
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0