Apex domains cannot have CNAME records.
Question and response
Question
dig marillac.edu.do. NS
Answer
marillac.edu.do. 5 NS ns65.hostgator.mx.
marillac.edu.do. 5 NS ns64.hostgator.mx.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0