Apex domains cannot have CNAME records.
Question and response
Question
dig polihermi.edu.do. NS
Answer
polihermi.edu.do. 3 NS ns3.lucushost.com.
polihermi.edu.do. 3 NS ns2.lucushost.com.
polihermi.edu.do. 3 NS ns1.lucushost.com.
Authority
The response has no authority records.
Additional
ns1.lucushost.com. 3 A 185.207.224.224
ns2.lucushost.com. 3 A 178.33.116.135
ns3.lucushost.com. 3 A 134.209.224.9
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0