Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-25.com. NS
Answer
awsdns-25.com. 1 NS g-ns-1753.awsdns-25.com.
awsdns-25.com. 1 NS g-ns-1177.awsdns-25.com.
awsdns-25.com. 1 NS g-ns-26.awsdns-25.com.
awsdns-25.com. 1 NS g-ns-601.awsdns-25.com.
Authority
The response has no authority records.
Additional
g-ns-26.awsdns-25.com. 1 A 205.251.192.26
g-ns-601.awsdns-25.com. 1 A 205.251.194.89
g-ns-1177.awsdns-25.com. 1 A 205.251.196.153
g-ns-1753.awsdns-25.com. 1 A 205.251.198.217
g-ns-26.awsdns-25.com. 1 AAAA 2600:9000:5300:1a00:0:0:0:1
g-ns-601.awsdns-25.com. 1 AAAA 2600:9000:5302:5900:0:0:0:1
g-ns-1177.awsdns-25.com. 1 AAAA 2600:9000:5304:9900:0:0:0:1
g-ns-1753.awsdns-25.com. 1 AAAA 2600:9000:5306:d900:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0