gateway.ssm.echoworx.net has no MX records.
Question and response
Question
dig gateway.ssm.echoworx.net. MX
Answer
The response has no answer records.
Authority
echoworx.net. 1800 SOA gina.ns.cloudflare.com. dns.cloudflare.com. 2397763177 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0