ns2.decknet.com has no MX records.
Question and response
Question
dig ns2.decknet.com. MX
Answer
The response has no answer records.
Authority
decknet.com. 3600 SOA ns1.decknet.com. postmaster.decknet.com. 2025012701 10800 3600 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0