Apex domains cannot have CNAME records.
Question and response
Question
dig 3mmatrix.hu. NS
Answer
3mmatrix.hu. 5 NS dns2.hu.
3mmatrix.hu. 5 NS dns3.hu.
3mmatrix.hu. 5 NS dns1.hu.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0