Apex domains cannot have CNAME records.
Question and response
Question
dig penteres.it. NS
Answer
penteres.it. 5 NS ns2.penteres.it.
penteres.it. 5 NS ns3.penteres.it.
penteres.it. 5 NS ns.penteres.it.
Authority
The response has no authority records.
Additional
ns.penteres.it. 5 A 178.250.64.66
ns2.penteres.it. 5 A 178.250.64.67
ns3.penteres.it. 5 A 31.193.16.11
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0