Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-23.com. NS
Answer
awsdns-23.com. 5 NS g-ns-1751.awsdns-23.com.
awsdns-23.com. 5 NS g-ns-1175.awsdns-23.com.
awsdns-23.com. 5 NS g-ns-24.awsdns-23.com.
awsdns-23.com. 5 NS g-ns-599.awsdns-23.com.
Authority
The response has no authority records.
Additional
g-ns-24.awsdns-23.com. 5 A 205.251.192.24
g-ns-599.awsdns-23.com. 5 A 205.251.194.87
g-ns-1175.awsdns-23.com. 5 A 205.251.196.151
g-ns-1751.awsdns-23.com. 5 A 205.251.198.215
g-ns-24.awsdns-23.com. 5 AAAA 2600:9000:5300:1800:0:0:0:1
g-ns-599.awsdns-23.com. 5 AAAA 2600:9000:5302:5700:0:0:0:1
g-ns-1175.awsdns-23.com. 5 AAAA 2600:9000:5304:9700:0:0:0:1
g-ns-1751.awsdns-23.com. 5 AAAA 2600:9000:5306:d700:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0