ns3.sencinet.com.br has no MX records.
Question and response
Question
dig ns3.sencinet.com.br. MX
Answer
The response has no answer records.
Authority
sencinet.com.br. 60 SOA ns1.sencinet.com.br. root.ns1.sencinet.com.br. 2025120601 10800 3600 604800 60
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0