Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-16.net. NS
Answer
awsdns-16.net. 5 NS g-ns-465.awsdns-16.net.
awsdns-16.net. 5 NS g-ns-1360.awsdns-16.net.
awsdns-16.net. 5 NS g-ns-786.awsdns-16.net.
awsdns-16.net. 5 NS g-ns-1936.awsdns-16.net.
Authority
The response has no authority records.
Additional
g-ns-465.awsdns-16.net. 5 A 205.251.193.209
g-ns-786.awsdns-16.net. 5 A 205.251.195.18
g-ns-1360.awsdns-16.net. 5 A 205.251.197.80
g-ns-1936.awsdns-16.net. 5 A 205.251.199.144
g-ns-465.awsdns-16.net. 5 AAAA 2600:9000:5301:d100:0:0:0:1
g-ns-786.awsdns-16.net. 5 AAAA 2600:9000:5303:1200:0:0:0:1
g-ns-1360.awsdns-16.net. 5 AAAA 2600:9000:5305:5000:0:0:0:1
g-ns-1936.awsdns-16.net. 5 AAAA 2600:9000:5307:9000:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0