mx4.nccdn.net has no MX records.
Question and response
Question
dig mx4.nccdn.net. MX
Answer
The response has no answer records.
Authority
nccdn.net. 1800 SOA lia.ns.cloudflare.com. dns.cloudflare.com. 2397707161 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0