ns3.serverlet.it has no MX records.
Question and response
Question
dig ns3.serverlet.it. MX
Answer
The response has no answer records.
Authority
serverlet.it. 3600 SOA ns1.serverlet.com. info.serverlet.com. 2025120366 28800 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0