Apex domains cannot have CNAME records.
Question and response
Question
dig llevon.com.br. NS
Answer
llevon.com.br. 5 NS ns10.llevon.com.br.
llevon.com.br. 5 NS ns30.llevon.com.br.
llevon.com.br. 5 NS ns20.llevon.com.br.
Authority
The response has no authority records.
Additional
ns10.llevon.com.br. 5 A 187.0.205.8
ns20.llevon.com.br. 5 A 187.0.205.9
ns30.llevon.com.br. 5 A 187.0.205.23
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0