Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-23.org. NS
Answer
awsdns-23.org. 5 NS g-ns-1050.awsdns-23.org.
awsdns-23.org. 5 NS g-ns-1623.awsdns-23.org.
awsdns-23.org. 5 NS g-ns-151.awsdns-23.org.
awsdns-23.org. 5 NS g-ns-729.awsdns-23.org.
Authority
The response has no authority records.
Additional
g-ns-151.awsdns-23.org. 5 A 205.251.192.151
g-ns-729.awsdns-23.org. 5 A 205.251.194.217
g-ns-1050.awsdns-23.org. 5 A 205.251.196.26
g-ns-1623.awsdns-23.org. 5 A 205.251.198.87
g-ns-151.awsdns-23.org. 5 AAAA 2600:9000:5300:9700:0:0:0:1
g-ns-729.awsdns-23.org. 5 AAAA 2600:9000:5302:d900:0:0:0:1
g-ns-1050.awsdns-23.org. 5 AAAA 2600:9000:5304:1a00:0:0:0:1
g-ns-1623.awsdns-23.org. 5 AAAA 2600:9000:5306:5700:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0