smtp-cacn.clouditalia.com has no CNAME records.
Question and response
Question
dig smtp-cacn.clouditalia.com. NS
Answer
The response has no answer records.
Authority
clouditalia.com. 7872 SOA mnt1.eutelia.it. hostmaster.eutelia.it. 2026021600 86400 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0