mx.mtamandic.com.br has no CNAME records.
Question and response
Question
dig mx.mtamandic.com.br. NS
Answer
The response has no answer records.
Authority
mtamandic.com.br. 172 SOA pns31.cloudns.net. support.cloudns.net. 2024042106 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0