app.cloudcone.com has no MX records.
Question and response
Question
dig app.cloudcone.com. MX
Answer
The response has no answer records.
Authority
cloudcone.com. 3600 SOA c3.cloudcone.net. admin.cloudcone.com. 2025091203 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0