Apex domains cannot have CNAME records.
Question and response
Question
dig celhost.eu. NS
Answer
celhost.eu. 5 NS ns2.pulsation.fr.
celhost.eu. 5 NS ns3.pulsation.fr.
celhost.eu. 5 NS ns1.pulsation.fr.
Authority
The response has no authority records.
Additional
ns1.pulsation.fr. 5 A 188.130.56.6
ns2.pulsation.fr. 5 A 212.106.102.54
ns3.pulsation.fr. 5 A 13.37.69.140
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0