Apex domains cannot have CNAME records.
Question and response
Question
dig greenpasturesbeef.com. NS
Answer
greenpasturesbeef.com. 5 NS ns-1016.awsdns-63.net.
greenpasturesbeef.com. 5 NS ns-1238.awsdns-26.org.
greenpasturesbeef.com. 5 NS ns-1233.awsdns-26.org.
greenpasturesbeef.com. 5 NS ns-1661.awsdns-15.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0