dns1.com4.com.br has no MX records.
Question and response
Question
dig dns1.com4.com.br. MX
Answer
The response has no answer records.
Authority
com4.com.br. 3600 SOA dns1.com4.com.br. admindominio.com4.com.br. 8241 86400 7200 3600000 7200
Additional
. 0 OPT ; payload 4000, xrcode 0, version 0, flags 0