mx.fastcon.it has no CNAME records.
Question and response
Question
dig mx.fastcon.it. NS
Answer
The response has no answer records.
Authority
fastcon.it. 3181 SOA dns.technorail.com. hostmaster.fastcon.it. 2025120801 86400 7200 2592000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0