smx.antispam.redehost.com.br has no CNAME records.
Question and response
Question
dig smx.antispam.redehost.com.br. NS
Answer
The response has no answer records.
Authority
antispam.redehost.com.br. 60 SOA redehostdns05.redehost.com.br. hostmaster.redehost.local. 1070 60 900 172800 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0