ns4.dialhost.com.br has no MX records.
Question and response
Question
dig ns4.dialhost.com.br. MX
Answer
The response has no answer records.
Authority
ns4.dialhost.com.br. 3600 SOA ns1.dialhost.com.br. alerta.dialhost.com.br. 2021082300 86400 7200 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0