Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-55.net. NS
Answer
awsdns-55.net. 5 NS g-ns-1399.awsdns-55.net.
awsdns-55.net. 5 NS g-ns-504.awsdns-55.net.
awsdns-55.net. 5 NS g-ns-825.awsdns-55.net.
awsdns-55.net. 5 NS g-ns-1975.awsdns-55.net.
Authority
The response has no authority records.
Additional
g-ns-504.awsdns-55.net. 5 A 205.251.193.248
g-ns-825.awsdns-55.net. 5 A 205.251.195.57
g-ns-1399.awsdns-55.net. 5 A 205.251.197.119
g-ns-1975.awsdns-55.net. 5 A 205.251.199.183
g-ns-504.awsdns-55.net. 5 AAAA 2600:9000:5301:f800:0:0:0:1
g-ns-825.awsdns-55.net. 5 AAAA 2600:9000:5303:3900:0:0:0:1
g-ns-1399.awsdns-55.net. 5 AAAA 2600:9000:5305:7700:0:0:0:1
g-ns-1975.awsdns-55.net. 5 AAAA 2600:9000:5307:b700:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0