mx.mymailwall.com has no MX records.
Question and response
Question
dig mx.mymailwall.com. MX
Answer
The response has no answer records.
Authority
mymailwall.com. 300 SOA ns3.domaindiscount24.net. tech.key-systems.net. 2025105833 10800 3600 604800 28800
Additional
. 0 OPT ; payload 1400, xrcode 0, version 0, flags 0