mx10.it.com has no CNAME records.
Question and response
Question
dig mx10.it.com. NS
Answer
The response has no answer records.
Authority
it.com. 1701 SOA ns1.it.com. dns.cloudflare.com. 2398029249 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0