Apex domains cannot have CNAME records.
Question and response
Question
dig awsdns-29.com. NS
Answer
awsdns-29.com. 5 NS g-ns-1757.awsdns-29.com.
awsdns-29.com. 5 NS g-ns-30.awsdns-29.com.
awsdns-29.com. 5 NS g-ns-605.awsdns-29.com.
awsdns-29.com. 5 NS g-ns-1181.awsdns-29.com.
Authority
The response has no authority records.
Additional
g-ns-30.awsdns-29.com. 5 A 205.251.192.30
g-ns-605.awsdns-29.com. 5 A 205.251.194.93
g-ns-1181.awsdns-29.com. 5 A 205.251.196.157
g-ns-1757.awsdns-29.com. 5 A 205.251.198.221
g-ns-30.awsdns-29.com. 5 AAAA 2600:9000:5300:1e00:0:0:0:1
g-ns-605.awsdns-29.com. 5 AAAA 2600:9000:5302:5d00:0:0:0:1
g-ns-1181.awsdns-29.com. 5 AAAA 2600:9000:5304:9d00:0:0:0:1
g-ns-1757.awsdns-29.com. 5 AAAA 2600:9000:5306:dd00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0