Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-30.com. NS
Answer
awsdns-30.com. 5 NS g-ns-31.awsdns-30.com.
awsdns-30.com. 5 NS g-ns-1758.awsdns-30.com.
awsdns-30.com. 5 NS g-ns-1182.awsdns-30.com.
awsdns-30.com. 5 NS g-ns-606.awsdns-30.com.
Authority
The response has no authority records.
Additional
g-ns-31.awsdns-30.com. 5 A 205.251.192.31
g-ns-606.awsdns-30.com. 5 A 205.251.194.94
g-ns-1182.awsdns-30.com. 5 A 205.251.196.158
g-ns-1758.awsdns-30.com. 5 A 205.251.198.222
g-ns-31.awsdns-30.com. 5 AAAA 2600:9000:5300:1f00:0:0:0:1
g-ns-606.awsdns-30.com. 5 AAAA 2600:9000:5302:5e00:0:0:0:1
g-ns-1182.awsdns-30.com. 5 AAAA 2600:9000:5304:9e00:0:0:0:1
g-ns-1758.awsdns-30.com. 5 AAAA 2600:9000:5306:de00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0