Apex domains cannot have CNAME records.
Question and response
Question
dig cuci.nl. NS
Answer
cuci.nl. 5 NS ns0031.secondary.cloudflare.com.
cuci.nl. 5 NS ns0142.secondary.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0