mx3.boysmania.com.br has no CNAME records.
Question and response
Question
dig mx3.boysmania.com.br. NS
Answer
The response has no answer records.
Authority
boysmania.com.br. 3314 SOA a10-dns-uolcsfe1.host.intranet. root.uol.com.br. 2012060757 7200 3600 432000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0