tsw01.kddi-web.com has no MX records.
Question and response
Question
dig tsw01.kddi-web.com. MX
Answer
The response has no answer records.
Authority
kddi-web.com. 100 SOA ns0.cpi.ad.jp. hostmaster.cpi.ad.jp. 2025070101 3600 900 3600000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0