Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-33.org. NS
Answer
awsdns-33.org. 5 NS g-ns-1633.awsdns-33.org.
awsdns-33.org. 5 NS g-ns-161.awsdns-33.org.
awsdns-33.org. 5 NS g-ns-739.awsdns-33.org.
awsdns-33.org. 5 NS g-ns-1060.awsdns-33.org.
Authority
The response has no authority records.
Additional
g-ns-161.awsdns-33.org. 5 A 205.251.192.161
g-ns-739.awsdns-33.org. 5 A 205.251.194.227
g-ns-1060.awsdns-33.org. 5 A 205.251.196.36
g-ns-1633.awsdns-33.org. 5 A 205.251.198.97
g-ns-161.awsdns-33.org. 5 AAAA 2600:9000:5300:a100:0:0:0:1
g-ns-739.awsdns-33.org. 5 AAAA 2600:9000:5302:e300:0:0:0:1
g-ns-1060.awsdns-33.org. 5 AAAA 2600:9000:5304:2400:0:0:0:1
g-ns-1633.awsdns-33.org. 5 AAAA 2600:9000:5306:6100:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0