ns10.nttsmc.com has no MX records.
Question and response
Question
dig ns10.nttsmc.com. MX
Answer
The response has no answer records.
Authority
nttsmc.com. 900 SOA ns.mcnet.ad.jp. postmaster.mcnet.ad.jp. 2026010801 10800 900 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0