Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-52.com. NS
Answer
awsdns-52.com. 5 NS g-ns-1780.awsdns-52.com.
awsdns-52.com. 5 NS g-ns-53.awsdns-52.com.
awsdns-52.com. 5 NS g-ns-628.awsdns-52.com.
awsdns-52.com. 5 NS g-ns-1204.awsdns-52.com.
Authority
The response has no authority records.
Additional
g-ns-53.awsdns-52.com. 5 A 205.251.192.53
g-ns-628.awsdns-52.com. 5 A 205.251.194.116
g-ns-1204.awsdns-52.com. 5 A 205.251.196.180
g-ns-1780.awsdns-52.com. 5 A 205.251.198.244
g-ns-53.awsdns-52.com. 5 AAAA 2600:9000:5300:3500:0:0:0:1
g-ns-628.awsdns-52.com. 5 AAAA 2600:9000:5302:7400:0:0:0:1
g-ns-1204.awsdns-52.com. 5 AAAA 2600:9000:5304:b400:0:0:0:1
g-ns-1780.awsdns-52.com. 5 AAAA 2600:9000:5306:f400:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0