Apex domains cannot have CNAME records.
Question and response
Question
dig isajuba.edu.do. NS
Answer
isajuba.edu.do. 5 NS ns1.bdm.microsoftonline.com.
isajuba.edu.do. 5 NS ns4.bdm.microsoftonline.com.
isajuba.edu.do. 5 NS ns3.bdm.microsoftonline.com.
isajuba.edu.do. 5 NS ns2.bdm.microsoftonline.com.
Authority
The response has no authority records.
Additional
ns1.bdm.microsoftonline.com. 4 A 13.107.236.208
ns2.bdm.microsoftonline.com. 4 A 150.171.21.208
ns3.bdm.microsoftonline.com. 4 A 204.14.183.208
ns4.bdm.microsoftonline.com. 4 A 208.84.5.208
ns1.bdm.microsoftonline.com. 4 AAAA 2603:1061:0:700:0:0:0:d0
ns2.bdm.microsoftonline.com. 4 AAAA 2620:1ec:8ec:700:0:0:0:d0
ns3.bdm.microsoftonline.com. 4 AAAA 2a01:111:4000:700:0:0:0:d0
ns4.bdm.microsoftonline.com. 4 AAAA 2620:1ec:bda:700:0:0:0:d0
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0