Apex domains cannot have CNAME records.
Question and response
Question
dig niif.hu. NS
Answer
niif.hu. 5 NS kubiac.iif.hu.
niif.hu. 5 NS ns2.sztaki.hbone.hu.
niif.hu. 5 NS ns2.iif.hu.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0