Apex domains cannot have CNAME records.
Question and response
Question
dig hilen.net. NS
Answer
hilen.net. 5 NS ns-256.awsdns-32.com.
hilen.net. 5 NS ns-177.awsdns-22.com.
hilen.net. 5 NS ns-115.awsdns-14.com.
hilen.net. 5 NS ns-1062.awsdns-04.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0