Apex domains cannot have CNAME records.
Question and response
Question
dig coccinelle.nl. NS
Answer
coccinelle.nl. 5 NS ns-k.dns.yourhosting.eu.
coccinelle.nl. 5 NS ns-o.dns.yourhosting.nu.
coccinelle.nl. 5 NS ns-j.dns.yourhosting.nl.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0