Apex domains cannot have CNAME records.
Question and response
Question
dig ms.hu. NS
Answer
ms.hu. 5 NS aruba-ns.microsystem.hu.
ms.hu. 5 NS ns.savaria.hu.
ms.hu. 5 NS ns.microsystem.hu.
Authority
The response has no authority records.
Additional
ns.savaria.hu. 5 A 77.221.39.2
ns.microsystem.hu. 5 A 195.184.4.1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0