smtp8.server2.mrelayip.com has no MX records.
Question and response
Question
dig smtp8.server2.mrelayip.com. MX
Answer
The response has no answer records.
Authority
mrelayip.com. 1800 SOA olga.ns.cloudflare.com. dns.cloudflare.com. 2396124095 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0