253.174.188.in-addr.arpa has no MX records.
Question and response
Question
dig 253.174.188.in-addr.arpa. MX
Answer
The response has no answer records.
Authority
253.174.188.in-addr.arpa. 1800 SOA ns1.m-online.net. hostmaster.m-net.de. 2025041102 14400 1800 1209600 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0