Apex domains cannot have CNAME records.
Question and response
Question
dig ipv4.tiscali.it. NS
Answer
ipv4.tiscali.it. 2 NS murdock.dns.tiscali.it.
ipv4.tiscali.it. 2 NS hannibal.dns.tiscali.it.
ipv4.tiscali.it. 2 NS barakus.dns.tiscali.it.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0