Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-37.com. NS
Answer
awsdns-37.com. 5 NS g-ns-1765.awsdns-37.com.
awsdns-37.com. 5 NS g-ns-1189.awsdns-37.com.
awsdns-37.com. 5 NS g-ns-38.awsdns-37.com.
awsdns-37.com. 5 NS g-ns-613.awsdns-37.com.
Authority
The response has no authority records.
Additional
g-ns-38.awsdns-37.com. 5 A 205.251.192.38
g-ns-613.awsdns-37.com. 5 A 205.251.194.101
g-ns-1189.awsdns-37.com. 5 A 205.251.196.165
g-ns-1765.awsdns-37.com. 5 A 205.251.198.229
g-ns-38.awsdns-37.com. 5 AAAA 2600:9000:5300:2600:0:0:0:1
g-ns-613.awsdns-37.com. 5 AAAA 2600:9000:5302:6500:0:0:0:1
g-ns-1189.awsdns-37.com. 5 AAAA 2600:9000:5304:a500:0:0:0:1
g-ns-1765.awsdns-37.com. 5 AAAA 2600:9000:5306:e500:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0