ns1.mss.mind.ne.jp has no MX records.
Question and response
Question
dig ns1.mss.mind.ne.jp. MX
Answer
The response has no answer records.
Authority
mss.mind.ne.jp. 1800 SOA ns1.mss.mind.ne.jp. postmaster.mss.mind.ne.jp. 14 1800 3600 604800 1800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0