nss.dn.ua has no MX records.
Question and response
Question
dig nss.dn.ua. MX
Answer
The response has no answer records.
Authority
dn.ua. 1800 SOA ho1.eunic.net.ua. info.eunic.net.ua. 2602230000 3600 1800 1814400 1800
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0