Apex domains cannot have CNAME records.
Question and response
Question
dig nubeluz.edu.do. NS
Answer
nubeluz.edu.do. 2 NS ns8348.hostgator.com.
nubeluz.edu.do. 2 NS ns8347.hostgator.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0