Apex domains cannot have CNAME records.
Question and response
Question
dig isisecure.it. NS
Answer
isisecure.it. 1 NS secondary.isiline.it.
isisecure.it. 1 NS ns.isiline.it.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0