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