Apex domains cannot have CNAME records.
Question and response
Question
dig treehousei.com. NS
Answer
treehousei.com. 5 NS ns-1958.awsdns-52.co.uk.
treehousei.com. 5 NS ns-732.awsdns-27.net.
treehousei.com. 5 NS ns-212.awsdns-26.com.
treehousei.com. 5 NS ns-1059.awsdns-04.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0