fs220.xbit.jp has no MX records.
Question and response
Question
dig fs220.xbit.jp. MX
Answer
The response has no answer records.
Authority
xbit.jp. 300 SOA ns01.xbit.jp. xunit-support.rakus.co.jp. 2025120402 14400 60 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0