Apex domains cannot have CNAME records.
Question and response
Question
dig eng.it. NS
Answer
eng.it. 5 NS ns03.eng.it.
eng.it. 5 NS ns01.eng.it.
Authority
The response has no authority records.
Additional
ns01.eng.it. 5 A 217.172.4.129
ns03.eng.it. 5 A 193.178.235.27
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0