Apex domains cannot have CNAME records.
Question and response
Question
dig vianova.it. NS
Answer
vianova.it. 5 NS dns.welcomeitalia.it.
vianova.it. 5 NS dnsslave.welcomeitalia.it.
Authority
The response has no authority records.
Additional
dns.welcomeitalia.it. 5 A 80.93.143.254
dnsslave.welcomeitalia.it. 5 A 80.93.143.250
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0