Apex domains cannot have CNAME records.
Question and response
Question
dig dns2.confirmatuevento.cl. NS
Answer
dns2.confirmatuevento.cl. 5 NS ns1.xprime3.cl.
dns2.confirmatuevento.cl. 5 NS ns2.xprime3.cl.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0