c4.cloudcone.net has no MX records.
Question and response
Question
dig c4.cloudcone.net. MX
Answer
The response has no answer records.
Authority
cloudcone.net. 3600 SOA ac1.cloudcone.net. admin.cloudcone.com. 2025101301 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0