Apex domains cannot have CNAME records.
Question and response
Question
dig hostihc.sk. NS
Answer
hostihc.sk. 5 NS ns3.sk.eserver.net.
hostihc.sk. 5 NS ns1.sk.eserver.net.
hostihc.sk. 5 NS ns2.sk.eserver.net.
hostihc.sk. 5 NS ns4.sk.eserver.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0