Apex domains cannot have CNAME records.
Question and response
Question
dig sysops.fi. NS
Answer
sysops.fi. 5 NS ben.ns.cloudflare.com.
sysops.fi. 5 NS joan.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
ben.ns.cloudflare.com. 4 A 108.162.193.103
ben.ns.cloudflare.com. 4 A 172.64.33.103
ben.ns.cloudflare.com. 4 A 173.245.59.103
joan.ns.cloudflare.com. 4 A 108.162.192.173
joan.ns.cloudflare.com. 4 A 172.64.32.173
joan.ns.cloudflare.com. 4 A 173.245.58.173
ben.ns.cloudflare.com. 4 AAAA 2606:4700:58:0:0:0:adf5:3b67
ben.ns.cloudflare.com. 4 AAAA 2803:f800:50:0:0:0:6ca2:c167
ben.ns.cloudflare.com. 4 AAAA 2a06:98c1:50:0:0:0:ac40:2167
joan.ns.cloudflare.com. 4 AAAA 2606:4700:50:0:0:0:adf5:3aad
joan.ns.cloudflare.com. 4 AAAA 2803:f800:50:0:0:0:6ca2:c0ad
joan.ns.cloudflare.com. 4 AAAA 2a06:98c1:50:0:0:0:ac40:20ad
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0