mf33-fr.cloudmails.net has no CNAME records.
Question and response
Question
dig mf33-fr.cloudmails.net. NS
Answer
The response has no answer records.
Authority
cloudmails.net. 3600 SOA ns1.cloudns.net. support.cloudns.net. 2025092901 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0