Apex domains cannot have CNAME records.
Question and response
Question
dig cpo.edu.do. NS
Answer
cpo.edu.do. 1 NS ns2.mdesignmediagroup.com.
cpo.edu.do. 1 NS ns1.mdesignmediagroup.com.
Authority
The response has no authority records.
Additional
ns1.mdesignmediagroup.com. 1 A 162.240.98.46
ns2.mdesignmediagroup.com. 1 A 162.240.98.47
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0