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