ns8.cloudoon.com has no MX records.
Question and response
Question
dig ns8.cloudoon.com. MX
Answer
The response has no answer records.
Authority
cloudoon.com. 1800 SOA hugh.ns.cloudflare.com. dns.cloudflare.com. 2398516255 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0