Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-06.com. NS
Answer
awsdns-06.com. 5 NS g-ns-1158.awsdns-06.com.
awsdns-06.com. 5 NS g-ns-1734.awsdns-06.com.
awsdns-06.com. 5 NS g-ns-7.awsdns-06.com.
awsdns-06.com. 5 NS g-ns-582.awsdns-06.com.
Authority
The response has no authority records.
Additional
g-ns-7.awsdns-06.com. 5 A 205.251.192.7
g-ns-582.awsdns-06.com. 5 A 205.251.194.70
g-ns-1158.awsdns-06.com. 5 A 205.251.196.134
g-ns-1734.awsdns-06.com. 5 A 205.251.198.198
g-ns-7.awsdns-06.com. 5 AAAA 2600:9000:5300:700:0:0:0:1
g-ns-582.awsdns-06.com. 5 AAAA 2600:9000:5302:4600:0:0:0:1
g-ns-1158.awsdns-06.com. 5 AAAA 2600:9000:5304:8600:0:0:0:1
g-ns-1734.awsdns-06.com. 5 AAAA 2600:9000:5306:c600:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0