mail.netplanety.com.br has no CNAME records.
Question and response
Question
dig mail.netplanety.com.br. NS
Answer
The response has no answer records.
Authority
netplanety.com.br. 3665 SOA a.ns.netplanety.com.br. hostmaster.netplanety.com.br. 2026030301 86400 7200 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0