Apex domains cannot have CNAME records.
Question and response
Question
dig 2i3.net. NS
Answer
2i3.net. 5 NS ns-895.awsdns-47.net.
2i3.net. 5 NS ns-1224.awsdns-25.org.
2i3.net. 5 NS ns-1997.awsdns-57.co.uk.
2i3.net. 5 NS ns-431.awsdns-53.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0