mail.cloudcenter.ec has no CNAME records.
Question and response
Question
dig mail.cloudcenter.ec. NS
Answer
The response has no answer records.
Authority
cloudcenter.ec. 900 SOA srv1.telconet.net. abuse.telconet.net. 109 10800 3600 2419200 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0