Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-43.com. NS
Answer
awsdns-43.com. 5 NS g-ns-44.awsdns-43.com.
awsdns-43.com. 5 NS g-ns-619.awsdns-43.com.
awsdns-43.com. 5 NS g-ns-1195.awsdns-43.com.
awsdns-43.com. 5 NS g-ns-1771.awsdns-43.com.
Authority
The response has no authority records.
Additional
g-ns-44.awsdns-43.com. 5 A 205.251.192.44
g-ns-619.awsdns-43.com. 5 A 205.251.194.107
g-ns-1195.awsdns-43.com. 5 A 205.251.196.171
g-ns-1771.awsdns-43.com. 5 A 205.251.198.235
g-ns-44.awsdns-43.com. 5 AAAA 2600:9000:5300:2c00:0:0:0:1
g-ns-619.awsdns-43.com. 5 AAAA 2600:9000:5302:6b00:0:0:0:1
g-ns-1195.awsdns-43.com. 5 AAAA 2600:9000:5304:ab00:0:0:0:1
g-ns-1771.awsdns-43.com. 5 AAAA 2600:9000:5306:eb00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0