mx.sms.messcube.it has no CNAME records.
Question and response
Question
dig mx.sms.messcube.it. NS
Answer
The response has no answer records.
Authority
messcube.it. 6089 SOA dns10-ha.interbusiness.it. staffdns.telecomitalia.it. 2019060687 86400 7200 2419200 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0