Apex domains cannot have CNAME records.
Question and response
Question
dig ibs.edu.do. NS
Answer
ibs.edu.do. 5 NS ns-705.awsdns-24.net.
ibs.edu.do. 5 NS ns-281.awsdns-35.com.
ibs.edu.do. 5 NS ns-1686.awsdns-18.co.uk.
ibs.edu.do. 5 NS ns-1255.awsdns-28.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0