Apex domains cannot have CNAME records.
Question and response
Question
dig grl.cl. NS
Answer
grl.cl. 5 NS ns3.hostmar.com.
grl.cl. 5 NS ns4.hostmar.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0