Apex domains cannot have CNAME records.
Question and response
Question
dig sfl.com.mx. NS
Answer
sfl.com.mx. 5 NS ns153.hostgator.mx.
sfl.com.mx. 5 NS ns152.hostgator.mx.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0