Apex domains cannot have CNAME records.
Question and response
Question
dig incavi.edu.do. NS
Answer
incavi.edu.do. 5 NS ns1.site4now.net.
incavi.edu.do. 5 NS ns3.site4now.net.
incavi.edu.do. 5 NS ns2.site4now.net.
Authority
The response has no authority records.
Additional
ns1.site4now.net. 5 A 70.39.73.45
ns1.site4now.net. 5 A 204.188.197.84
ns1.site4now.net. 5 A 204.188.197.246
ns2.site4now.net. 5 A 45.58.159.232
ns2.site4now.net. 5 A 45.58.159.233
ns2.site4now.net. 5 A 208.98.36.41
ns3.site4now.net. 5 A 45.58.159.230
ns3.site4now.net. 5 A 45.58.159.231
ns3.site4now.net. 5 A 208.98.36.42
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0