Apex domains cannot have CNAME records.
Question and response
Question
dig wznetlem.com.br. NS
Answer
wznetlem.com.br. 5 NS dns-aut-01.wznetlem.com.br.
wznetlem.com.br. 5 NS dns-aut-02.wznetlem.com.br.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0