Apex domains cannot have CNAME records.
Question and response
Question
dig seeweb.it. NS
Answer
seeweb.it. 5 NS dns.seeweb.it.
seeweb.it. 5 NS dns2.seeweb.it.
Authority
The response has no authority records.
Additional
dns.seeweb.it. 5 A 212.25.160.10
dns2.seeweb.it. 5 A 85.94.194.108
dns2.seeweb.it. 5 AAAA 2001:4b78:0:0:0:0:0:22
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0