mx-1.aams4.jp has no MX records.
Question and response
Question
dig mx-1.aams4.jp. MX
Answer
The response has no answer records.
Authority
aams4.jp. 300 SOA www1.aams.jp. aams-support.bbsec.co.jp. 2025040401 300 60 604800 300
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0