Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-56.org. NS
Answer
awsdns-56.org. 5 NS g-ns-1656.awsdns-56.org.
awsdns-56.org. 5 NS g-ns-1083.awsdns-56.org.
awsdns-56.org. 5 NS g-ns-184.awsdns-56.org.
awsdns-56.org. 5 NS g-ns-762.awsdns-56.org.
Authority
The response has no authority records.
Additional
g-ns-184.awsdns-56.org. 5 A 205.251.192.184
g-ns-762.awsdns-56.org. 5 A 205.251.194.250
g-ns-1083.awsdns-56.org. 5 A 205.251.196.59
g-ns-1656.awsdns-56.org. 5 A 205.251.198.120
g-ns-184.awsdns-56.org. 5 AAAA 2600:9000:5300:b800:0:0:0:1
g-ns-762.awsdns-56.org. 5 AAAA 2600:9000:5302:fa00:0:0:0:1
g-ns-1083.awsdns-56.org. 5 AAAA 2600:9000:5304:3b00:0:0:0:1
g-ns-1656.awsdns-56.org. 5 AAAA 2600:9000:5306:7800:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0