Apex domains cannot have CNAME records.
Question and response
Question
dig coopinfa.mil.do. NS
Answer
coopinfa.mil.do. 5 NS ed.ns.cloudflare.com.
coopinfa.mil.do. 5 NS elle.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0