ns2.dns.nic.win has no MX records.
Question and response
Question
dig ns2.dns.nic.win. MX
Answer
The response has no answer records.
Authority
nic.win. 900 SOA ns1.dns.nic.win. admin.tldns.godaddy. 1772037948 1800 300 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0