mmx.swatco.com has no MX records.
Question and response
Question
dig mmx.swatco.com. MX
Answer
The response has no answer records.
Authority
swatco.com. 600 SOA ns1.swatco.com. noc.swat.coop. 2026021601 1800 600 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0