Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-45.com. NS
Answer
awsdns-45.com. 5 NS g-ns-621.awsdns-45.com.
awsdns-45.com. 5 NS g-ns-1773.awsdns-45.com.
awsdns-45.com. 5 NS g-ns-46.awsdns-45.com.
awsdns-45.com. 5 NS g-ns-1197.awsdns-45.com.
Authority
The response has no authority records.
Additional
g-ns-46.awsdns-45.com. 5 A 205.251.192.46
g-ns-621.awsdns-45.com. 5 A 205.251.194.109
g-ns-1197.awsdns-45.com. 5 A 205.251.196.173
g-ns-1773.awsdns-45.com. 5 A 205.251.198.237
g-ns-46.awsdns-45.com. 5 AAAA 2600:9000:5300:2e00:0:0:0:1
g-ns-621.awsdns-45.com. 5 AAAA 2600:9000:5302:6d00:0:0:0:1
g-ns-1197.awsdns-45.com. 5 AAAA 2600:9000:5304:ad00:0:0:0:1
g-ns-1773.awsdns-45.com. 5 AAAA 2600:9000:5306:ed00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0