sg01extb.greenradar.com has no MX records.
Question and response
Question
dig sg01extb.greenradar.com. MX
Answer
The response has no answer records.
Authority
greenradar.com. 600 SOA pdns07.domaincontrol.com. dns.jomax.net. 2026022400 28800 7200 604800 600
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0