Apex domains cannot have CNAME records.
Question and response
Question
dig cepmsd.edu.do. NS
Answer
cepmsd.edu.do. 5 NS ns70.dnns.net.
cepmsd.edu.do. 5 NS ns71.dnns.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0