Apex domains cannot have CNAME records.
Question and response
Question
dig mydomain.ro. NS
Answer
mydomain.ro. 5 NS ns1.meganameservers.eu.
mydomain.ro. 5 NS ns2.meganameservers.eu.
mydomain.ro. 5 NS ns3.meganameservers.eu.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0