Apex domains cannot have CNAME records.
Question and response
Question
dig sinc.cl. NS
Answer
sinc.cl. 5 NS ns1.hostname.cl.
sinc.cl. 5 NS ns2.hostname.cl.
sinc.cl. 5 NS ns3.hostname.cl.
sinc.cl. 5 NS ns4.hostname.cl.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0