Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-15.com. NS
Answer
awsdns-15.com. 1 NS g-ns-591.awsdns-15.com.
awsdns-15.com. 1 NS g-ns-1743.awsdns-15.com.
awsdns-15.com. 1 NS g-ns-16.awsdns-15.com.
awsdns-15.com. 1 NS g-ns-1167.awsdns-15.com.
Authority
The response has no authority records.
Additional
g-ns-16.awsdns-15.com. 1 A 205.251.192.16
g-ns-591.awsdns-15.com. 1 A 205.251.194.79
g-ns-1167.awsdns-15.com. 1 A 205.251.196.143
g-ns-1743.awsdns-15.com. 1 A 205.251.198.207
g-ns-16.awsdns-15.com. 1 AAAA 2600:9000:5300:1000:0:0:0:1
g-ns-591.awsdns-15.com. 1 AAAA 2600:9000:5302:4f00:0:0:0:1
g-ns-1167.awsdns-15.com. 1 AAAA 2600:9000:5304:8f00:0:0:0:1
g-ns-1743.awsdns-15.com. 1 AAAA 2600:9000:5306:cf00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0