dns1.netecom.net.br has no MX records.
Question and response
Question
dig dns1.netecom.net.br. MX
Answer
The response has no answer records.
Authority
netecom.net.br. 7200 SOA ns1.netecom.net.br. rudson.netecom.net.br. 2021102100 10800 900 604800 86400
Additional
. 0 OPT [{Extended_DNS_Error: PROHIBITED}] ; payload 1232, xrcode 0, version 0, flags 0