Apex domains cannot have CNAME records.
Question and response
Question
dig cesa.edu.do. NS
Answer
cesa.edu.do. 5 NS dns1.supremedns.com.
cesa.edu.do. 5 NS dns4.supremedns.com.
cesa.edu.do. 5 NS dns3.supremedns.com.
cesa.edu.do. 5 NS dns2.supremedns.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0