Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-33.net. NS
Answer
awsdns-33.net. 5 NS g-ns-482.awsdns-33.net.
awsdns-33.net. 5 NS g-ns-1377.awsdns-33.net.
awsdns-33.net. 5 NS g-ns-803.awsdns-33.net.
awsdns-33.net. 5 NS g-ns-1953.awsdns-33.net.
Authority
The response has no authority records.
Additional
g-ns-482.awsdns-33.net. 5 A 205.251.193.226
g-ns-803.awsdns-33.net. 5 A 205.251.195.35
g-ns-1377.awsdns-33.net. 5 A 205.251.197.97
g-ns-1953.awsdns-33.net. 5 A 205.251.199.161
g-ns-482.awsdns-33.net. 5 AAAA 2600:9000:5301:e200:0:0:0:1
g-ns-803.awsdns-33.net. 5 AAAA 2600:9000:5303:2300:0:0:0:1
g-ns-1377.awsdns-33.net. 5 AAAA 2600:9000:5305:6100:0:0:0:1
g-ns-1953.awsdns-33.net. 5 AAAA 2600:9000:5307:a100:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0