Apex domains cannot have CNAME records.
Question and response
Question
dig tefilin.org. NS
Answer
tefilin.org. 2 NS ns-1157.awsdns-16.org.
tefilin.org. 2 NS ns-1713.awsdns-22.co.uk.
tefilin.org. 2 NS ns-306.awsdns-38.com.
tefilin.org. 2 NS ns-956.awsdns-55.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0