mx.aams3.jp has no MX records.
Question and response
Question
dig mx.aams3.jp. MX
Answer
The response has no answer records.
Authority
aams3.jp. 300 SOA www1.aams.jp. aams-support.bbsec.co.jp. 2020050101 300 60 604800 300
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0