nordns.crowncloud.net has no MX records.
Question and response
Question
dig nordns.crowncloud.net. MX
Answer
The response has no answer records.
Authority
crowncloud.net. 1800 SOA elsa.ns.cloudflare.com. dns.cloudflare.com. 2397762044 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0