Apex domains cannot have CNAME records.
Question and response
Question
dig uio.puntonet.ec. NS
Answer
uio.puntonet.ec. 2 NS server.punto.net.ec.
uio.puntonet.ec. 2 NS dns2.punto.net.ec.
Authority
The response has no authority records.
Additional
dns2.punto.net.ec. 1 A 200.105.243.94
server.punto.net.ec. 1 A 179.49.26.138
server.punto.net.ec. 1 A 200.105.225.2
dns2.punto.net.ec. 1 AAAA 2800:5f0:800:15:0:0:0:2
server.punto.net.ec. 1 AAAA 2800:5f0:800:13:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0