Apex domains cannot have CNAME records.
Question and response
Question
dig webnode.io. NS
Answer
webnode.io. 3 NS ns-1593.awsdns-07.co.uk.
webnode.io. 3 NS ns-405.awsdns-50.com.
webnode.io. 3 NS ns-644.awsdns-16.net.
webnode.io. 3 NS ns-1099.awsdns-09.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0