Apex domains cannot have CNAME records.
Question and response
Question
dig flockpin.co. NS
Answer
flockpin.co. 5 NS ns-738.awsdns-28.net.
flockpin.co. 5 NS ns-1922.awsdns-48.co.uk.
flockpin.co. 5 NS ns-28.awsdns-03.com.
flockpin.co. 5 NS ns-1400.awsdns-47.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0