Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-28.net. NS
Answer
awsdns-28.net. 5 NS g-ns-798.awsdns-28.net.
awsdns-28.net. 5 NS g-ns-477.awsdns-28.net.
awsdns-28.net. 5 NS g-ns-1948.awsdns-28.net.
awsdns-28.net. 5 NS g-ns-1372.awsdns-28.net.
Authority
The response has no authority records.
Additional
g-ns-477.awsdns-28.net. 5 A 205.251.193.221
g-ns-798.awsdns-28.net. 5 A 205.251.195.30
g-ns-1372.awsdns-28.net. 5 A 205.251.197.92
g-ns-1948.awsdns-28.net. 5 A 205.251.199.156
g-ns-477.awsdns-28.net. 5 AAAA 2600:9000:5301:dd00:0:0:0:1
g-ns-798.awsdns-28.net. 5 AAAA 2600:9000:5303:1e00:0:0:0:1
g-ns-1372.awsdns-28.net. 5 AAAA 2600:9000:5305:5c00:0:0:0:1
g-ns-1948.awsdns-28.net. 5 AAAA 2600:9000:5307:9c00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0