mx1.nuro.jp has no MX records.
Question and response
Question
dig mx1.nuro.jp. MX
Answer
The response has no answer records.
Authority
nuro.jp. 600 SOA mv-dnsm.nuro.jp. hostmaster.nuro.jp. 1771393520 3600 300 60200 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0