Apex domains cannot have CNAME records.
Question and response
Question
dig cidatab.edu.do. NS
Answer
cidatab.edu.do. 5 NS ns-1746.awsdns-26.co.uk.
cidatab.edu.do. 5 NS ns-1176.awsdns-19.org.
cidatab.edu.do. 5 NS ns-31.awsdns-03.com.
cidatab.edu.do. 5 NS ns-586.awsdns-09.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0