ns2.onnettelecom.com.br has no MX records.
Question and response
Question
dig ns2.onnettelecom.com.br. MX
Answer
The response has no answer records.
Authority
onnettelecom.com.br. 86400 SOA ns1.onnettelecom.com.br. root.ns1.onnettelecom.com.br. 2025082203 28800 7200 2419200 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0