spf02.suumo.com has no MX records.
Question and response
Question
dig spf02.suumo.com. MX
Answer
The response has no answer records.
Authority
suumo.com. 300 SOA ns1.x.recruit.co.jp. postmaster.x.recruit.co.jp. 2026021801 10800 3600 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0