Apex domains cannot have CNAME records.
Question and response
Question
dig jce.gov.do. NS
Answer
jce.gov.do. 5 NS dns10.midominio.do.
jce.gov.do. 5 NS dns20.midominio.do.
jce.gov.do. 5 NS dns30.midominio.do.
jce.gov.do. 5 NS dns40.midominio.do.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0