Apex domains cannot have CNAME records.
Question and response
Question
dig wcs.net.br. NS
Answer
wcs.net.br. 5 NS ns4.wcs.net.br.
wcs.net.br. 5 NS ns3.wcs.net.br.
Authority
The response has no authority records.
Additional
ns3.wcs.net.br. 5 A 187.62.220.2
ns4.wcs.net.br. 5 A 187.62.209.6
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0