mx1.systemar.com.br has no CNAME records.
Question and response
Question
dig mx1.systemar.com.br. NS
Answer
The response has no answer records.
Authority
systemar.com.br. 2908 SOA ns1.systemar.com.br. eliel.systemar.com.br. 2024052810 3600 900 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0