Apex domains cannot have CNAME records.
Question and response
Question
dig niatro.com. NS
Answer
niatro.com. 4 NS ns383.hostgator.com.br.
niatro.com. 4 NS ns382.hostgator.com.br.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0