mail.interpow.net has no CNAME records.
Question and response
Question
dig mail.interpow.net. NS
Answer
The response has no answer records.
Authority
interpow.net. 2704 SOA pns1.cloudns.net. support.cloudns.net. 2020053013 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0