Apex domains cannot have CNAME records.
Question and response
Question
dig dentium.edu.do. NS
Answer
dentium.edu.do. 5 NS ns2.carlosnamoc.com.
dentium.edu.do. 5 NS ns1.carlosnamoc.com.
Authority
The response has no authority records.
Additional
ns1.carlosnamoc.com. 5 A 50.31.188.99
ns2.carlosnamoc.com. 5 A 50.31.188.100
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0