Apex domains cannot have CNAME records.
Question and response
Question
dig fluoo.com. NS
Answer
fluoo.com. 5 NS vil.fluoo.com.
fluoo.com. 5 NS bipbip.fluoo.com.
Authority
The response has no authority records.
Additional
vil.fluoo.com. 5 A 51.91.48.87
bipbip.fluoo.com. 5 A 152.228.132.9
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0