Apex domains cannot have CNAME records.
Question and response
Question
dig nsgrid.net. NS
Answer
nsgrid.net. 3 NS ns2.nsgrid.net.
nsgrid.net. 3 NS ns1.nsgrid.net.
Authority
The response has no authority records.
Additional
ns1.nsgrid.net. 3 A 62.210.5.1
ns2.nsgrid.net. 3 A 62.210.6.1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0