Apex domains cannot have CNAME records.
Question and response
Question
dig ceduema.edu.do. NS
Answer
ceduema.edu.do. 4 NS ns68.hostgator.mx.
ceduema.edu.do. 4 NS ns69.hostgator.mx.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0