Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-15.net. NS
Answer
awsdns-15.net. 5 NS g-ns-1359.awsdns-15.net.
awsdns-15.net. 5 NS g-ns-1935.awsdns-15.net.
awsdns-15.net. 5 NS g-ns-464.awsdns-15.net.
awsdns-15.net. 5 NS g-ns-785.awsdns-15.net.
Authority
The response has no authority records.
Additional
g-ns-464.awsdns-15.net. 5 A 205.251.193.208
g-ns-785.awsdns-15.net. 5 A 205.251.195.17
g-ns-1359.awsdns-15.net. 5 A 205.251.197.79
g-ns-1935.awsdns-15.net. 5 A 205.251.199.143
g-ns-464.awsdns-15.net. 5 AAAA 2600:9000:5301:d000:0:0:0:1
g-ns-785.awsdns-15.net. 5 AAAA 2600:9000:5303:1100:0:0:0:1
g-ns-1359.awsdns-15.net. 5 AAAA 2600:9000:5305:4f00:0:0:0:1
g-ns-1935.awsdns-15.net. 5 AAAA 2600:9000:5307:8f00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0