Apex domains cannot have CNAME records.
Question and response
Question
dig marina.mil.do. NS
Answer
marina.mil.do. 5 NS lars.ns.cloudflare.com.
marina.mil.do. 5 NS karina.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
lars.ns.cloudflare.com. 2 A 108.162.193.195
lars.ns.cloudflare.com. 2 A 172.64.33.195
lars.ns.cloudflare.com. 2 A 173.245.59.195
karina.ns.cloudflare.com. 2 A 108.162.192.178
karina.ns.cloudflare.com. 2 A 172.64.32.178
karina.ns.cloudflare.com. 2 A 173.245.58.178
lars.ns.cloudflare.com. 2 AAAA 2606:4700:58:0:0:0:adf5:3bc3
lars.ns.cloudflare.com. 2 AAAA 2803:f800:50:0:0:0:6ca2:c1c3
lars.ns.cloudflare.com. 2 AAAA 2a06:98c1:50:0:0:0:ac40:21c3
karina.ns.cloudflare.com. 2 AAAA 2606:4700:50:0:0:0:adf5:3ab2
karina.ns.cloudflare.com. 2 AAAA 2803:f800:50:0:0:0:6ca2:c0b2
karina.ns.cloudflare.com. 2 AAAA 2a06:98c1:50:0:0:0:ac40:20b2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0