Apex domains cannot have CNAME records.
Question and response
Question
dig sloansnewyork.org. NS
Answer
sloansnewyork.org. 5 NS ns-794.awsdns-35.net.
sloansnewyork.org. 5 NS ns-1053.awsdns-03.org.
sloansnewyork.org. 5 NS ns-1164.awsdns-17.org.
sloansnewyork.org. 5 NS ns-477.awsdns-59.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0