Apex domains cannot have CNAME records.
Question and response
Question
dig gre-ase.com. NS
Answer
gre-ase.com. 2 NS ns-584.awsdns-09.net.
gre-ase.com. 2 NS ns-1154.awsdns-16.org.
gre-ase.com. 2 NS ns-107.awsdns-13.com.
gre-ase.com. 2 NS ns-860.awsdns-43.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0