Apex domains cannot have CNAME records.
Question and response
Question
dig libanswers.com. NS
Answer
libanswers.com. 5 NS ns-591.awsdns-09.net.
libanswers.com. 5 NS ns-1830.awsdns-36.co.uk.
libanswers.com. 5 NS ns-140.awsdns-17.com.
libanswers.com. 5 NS ns-1474.awsdns-56.org.
Authority
The response has no authority records.
Additional
ns-591.awsdns-09.net. 3 A 205.251.194.79
ns-591.awsdns-09.net. 3 AAAA 2600:9000:5302:4f00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0