Apex domains cannot have CNAME records.
Question and response
Question
dig colegiopsicopedagogicolosalamos.edu.do. NS
Answer
colegiopsicopedagogicolosalamos.edu.do. 5 NS horizon.dns-parking.com.
colegiopsicopedagogicolosalamos.edu.do. 5 NS orbit.dns-parking.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0