ns2.chrtelecom.net.br has no MX records.
Question and response
Question
dig ns2.chrtelecom.net.br. MX
Answer
The response has no answer records.
Authority
chrtelecom.net.br. 86400 SOA ns1.chrtelecom.net.br. root.chrtelecom.net.br. 2012031600 28800 7200 864000 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0