Apex domains cannot have CNAME records.
Question and response
Question
dig ikoula.nl. NS
Answer
ikoula.nl. 5 NS ns1.ikoula.fr.
ikoula.nl. 5 NS ns2.ikoula.fr.
ikoula.nl. 5 NS ns3.ikoula.fr.
Authority
The response has no authority records.
Additional
ns1.ikoula.fr. 5 A 213.246.33.228
ns2.ikoula.fr. 5 A 213.246.33.229
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0