Apex domains cannot have CNAME records.
Question and response
Question
dig pjsr.edu.do. NS
Answer
pjsr.edu.do. 5 NS ns1.pjsr.edu.do.
pjsr.edu.do. 5 NS ns2.pjsr.edu.do.
Authority
The response has no authority records.
Additional
ns1.pjsr.edu.do. 5 A 45.15.124.168
ns1.pjsr.edu.do. 5 A 89.116.171.250
ns2.pjsr.edu.do. 5 A 89.116.171.250
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0