Apex domains cannot have CNAME records.
Question and response
Question
dig hn. NS
Answer
hn. 5 NS ns2.anycastdns.cz.
hn. 5 NS pch-anycast.rds.org.hn.
hn. 5 NS a.lactld.org.
hn. 5 NS ns1.anycastdns.cz.
Authority
The response has no authority records.
Additional
a.lactld.org. 2 A 200.0.68.10
ns1.anycastdns.cz. 5 A 185.38.108.108
ns2.anycastdns.cz. 5 A 185.28.194.194
pch-anycast.rds.org.hn. 157828 A 204.61.216.64
a.lactld.org. 2 AAAA 2801:14:a000:0:0:0:0:10
ns1.anycastdns.cz. 5 AAAA 2a00:fea0:dead:0:0:0:0:beef
pch-anycast.rds.org.hn. 157828 AAAA 2001:500:14:6064:ad:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0