customers.clickdimensions.com has no MX records.
Question and response
Question
dig customers.clickdimensions.com. MX
Answer
The response has no answer records.
Authority
clickdimensions.com. 600 SOA pdns13.domaincontrol.com. dns.jomax.net. 2026022000 28800 7200 604800 600
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0