Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-12.com. NS
Answer
awsdns-12.com. 5 NS g-ns-588.awsdns-12.com.
awsdns-12.com. 5 NS g-ns-1740.awsdns-12.com.
awsdns-12.com. 5 NS g-ns-13.awsdns-12.com.
awsdns-12.com. 5 NS g-ns-1164.awsdns-12.com.
Authority
The response has no authority records.
Additional
g-ns-13.awsdns-12.com. 5 A 205.251.192.13
g-ns-588.awsdns-12.com. 5 A 205.251.194.76
g-ns-1164.awsdns-12.com. 5 A 205.251.196.140
g-ns-1740.awsdns-12.com. 5 A 205.251.198.204
g-ns-13.awsdns-12.com. 5 AAAA 2600:9000:5300:d00:0:0:0:1
g-ns-588.awsdns-12.com. 5 AAAA 2600:9000:5302:4c00:0:0:0:1
g-ns-1164.awsdns-12.com. 5 AAAA 2600:9000:5304:8c00:0:0:0:1
g-ns-1740.awsdns-12.com. 5 AAAA 2600:9000:5306:cc00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0