Apex domains cannot have CNAME records.
Question and response
Question
dig gnum.info. NS
Answer
gnum.info. 5 NS ns1.gnum.info.
gnum.info. 5 NS ns2.gnum.info.
Authority
The response has no authority records.
Additional
ns1.gnum.info. 5 A 173.252.192.138
ns2.gnum.info. 5 A 92.222.128.211
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0