Apex domains cannot have CNAME records.
Question and response
Question
dig enj.edu.do. NS
Answer
enj.edu.do. 5 NS ns-2039.awsdns-62.co.uk.
enj.edu.do. 5 NS ns-243.awsdns-30.com.
enj.edu.do. 5 NS ns-816.awsdns-38.net.
enj.edu.do. 5 NS ns-1025.awsdns-00.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0