spf.etius.jp has no MX records.
Question and response
Question
dig spf.etius.jp. MX
Answer
The response has no answer records.
Authority
spf.etius.jp. 3600 SOA ns3.sphere.ad.jp. dns.sphere.ad.jp. 2024032201 86400 21600 2419200 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0