Apex domains cannot have CNAME records.
Question and response
Question
dig webflash.net.br. NS
Answer
webflash.net.br. 4 NS lady.ns.cloudflare.com.
webflash.net.br. 4 NS rocco.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0