Apex domains cannot have CNAME records.
Question and response
Question
dig sn1.eutelia.it. NS
Answer
sn1.eutelia.it. 5 NS ns2.eutelia.it.
sn1.eutelia.it. 5 NS ns1.eutelia.it.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0