Apex domains cannot have CNAME records.
Question and response
Question
dig regiespfs.net. NS
Answer
regiespfs.net. 5 NS luce-dns-2.regiespfs.net.
regiespfs.net. 5 NS srv-dns-ext.ispccin.fr.
regiespfs.net. 5 NS gellainville-dns-1.regiespfs.net.
Authority
The response has no authority records.
Additional
luce-dns-2.regiespfs.net. 5 A 87.238.144.67
gellainville-dns-1.regiespfs.net. 5 A 87.238.144.98
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0