mta-o2.ampernet.com.br has no MX records.
Question and response
Question
dig mta-o2.ampernet.com.br. MX
Answer
The response has no answer records.
Authority
ampernet.com.br. 3600 SOA ns1.ampernet.com.br. postmaster.ampernet.com.br. 2025102805 3600 3600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0