fttx.cable-17712214.predialnet.com.br has no MX records.
Question and response
Question
dig fttx.cable-17712214.predialnet.com.br. MX
Answer
The response has no answer records.
Authority
predialnet.com.br. 7200 SOA ns1.predialnet.com.br. sistemas.predialnet.com.br. 2011070182 7200 7200 3600000 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0