a.gw.cipnet.com.br has no MX records.
Question and response
Question
dig a.gw.cipnet.com.br. MX
Answer
The response has no answer records.
Authority
cipnet.com.br. 86400 SOA a.ns.cipnet.com.br. postmaster.cipnet.com.br. 2026020900 14400 7200 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0