Apex domains cannot have CNAME records.
Question and response
Question
dig distrito0603.edu.do. NS
Answer
distrito0603.edu.do. 5 NS hermes.dns-parking.com.
distrito0603.edu.do. 5 NS artemis.dns-parking.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0