dns.ne.jp has no MX records.
Question and response
Question
dig dns.ne.jp. MX
Answer
The response has no answer records.
Authority
dns.ne.jp. 900 SOA dns.sakura.ad.jp. dns.sakura.ad.jp. 2024010600 900 300 3600000 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0