Apex domains cannot have CNAME records.
Question and response
Question
dig learningcities2020.org. NS
Answer
learningcities2020.org. 4 NS ns-785.awsdns-34.net.
learningcities2020.org. 4 NS ns-1055.awsdns-03.org.
learningcities2020.org. 4 NS ns-1733.awsdns-24.co.uk.
learningcities2020.org. 4 NS ns-360.awsdns-45.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0