ns.atsuta.awk.jp has no MX records.
Question and response
Question
dig ns.atsuta.awk.jp. MX
Answer
The response has no answer records.
Authority
atsuta.awk.jp. 300 SOA ns.atsuta.awk.jp. system.egg.co.jp. 1756878128 14400 60 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0