202.131.202.in-addr.arpa has no MX records.
Question and response
Question
dig 202.131.202.in-addr.arpa. MX
Answer
The response has no answer records.
Authority
202.131.202.in-addr.arpa. 300 SOA ns2.bit-isle.co.jp. root.bit-isle.co.jp. 2024092500 3600 1800 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0