mail.carerix.net has no CNAME records.
Question and response
Question
dig mail.carerix.net. NS
Answer
The response has no answer records.
Authority
carerix.net. 1237 SOA ns10.digicertdns.com. dns.digicertdns.com. 2009011444 43200 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0