mx.postacert.it.net has no MX records.
Question and response
Question
dig mx.postacert.it.net. MX
Answer
The response has no answer records.
Authority
postacert.it.net. 900 SOA dns.it.net. dns.reevodns.it. 2025092601 86400 7200 2592000 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0