hs.ctc.jp has no MX records.
Question and response
Question
dig hs.ctc.jp. MX
Answer
The response has no answer records.
Authority
hs.ctc.jp. 300 SOA ns1.hs.ctc.jp. admin.dc.ctc.ad.jp. 2021030200 28800 7200 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0