nssar.ctbc.com.br has no MX records.
Question and response
Question
dig nssar.ctbc.com.br. MX
Answer
The response has no answer records.
Authority
ctbc.com.br. 1800 SOA tricia.ns.cloudflare.com. dns.cloudflare.com. 2396753724 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0