Apex domains cannot have CNAME records.
Question and response
Question
dig zsurob.hu. NS
Answer
zsurob.hu. 5 NS ns13.zoneedit.com.
zsurob.hu. 5 NS ns4.zoneedit.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0