Apex domains cannot have CNAME records.
Question and response
Question
dig pfserver.it. NS
Answer
pfserver.it. 5 NS dns100.ovh.net.
pfserver.it. 5 NS ns100.ovh.net.
Authority
The response has no authority records.
Additional
ns100.ovh.net. 2 A 5.135.44.185
dns100.ovh.net. 2 A 5.135.250.177
ns100.ovh.net. 2 AAAA 2001:41d0:b00:f400:0:0:0:2
dns100.ovh.net. 2 AAAA 2001:41d0:d00:fa00:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0