Apex domains cannot have CNAME records.
Question and response
Question
dig gratuit-poker.org. NS
Answer
gratuit-poker.org. 5 NS ns-86.awsdns-10.com.
gratuit-poker.org. 5 NS ns-478.awsdns-59.com.
gratuit-poker.org. 5 NS ns-449.awsdns-56.com.
gratuit-poker.org. 5 NS ns-916.awsdns-50.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0