Apex domains cannot have CNAME records.
Question and response
Question
dig hostgator-br.com. NS
Answer
hostgator-br.com. 4 NS ns15.abovedomains.com.
hostgator-br.com. 4 NS ns16.abovedomains.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0