Apex domains cannot have CNAME records.
Question and response
Question
dig universidaddelcaribe.edu.do. NS
Answer
universidaddelcaribe.edu.do. 5 NS ns-331.awsdns-41.com.
universidaddelcaribe.edu.do. 5 NS ns-654.awsdns-17.net.
universidaddelcaribe.edu.do. 5 NS ns-1195.awsdns-21.org.
universidaddelcaribe.edu.do. 5 NS ns-1593.awsdns-07.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0