mail.mcldr.com has no CNAME records.
Question and response
Question
dig mail.mcldr.com. NS
Answer
The response has no answer records.
Authority
mcldr.com. 2545 SOA pns31.cloudns.net. support.cloudns.net. 2025082632 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0