gibmxdr.com has no MX records.
Question and response
Question
dig gibmxdr.com. MX
Answer
The response has no answer records.
Authority
gibmxdr.com. 1800 SOA heidi.ns.cloudflare.com. dns.cloudflare.com. 2397619785 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0