Apex domains cannot have CNAME records.
Question and response
Question
dig septrum.org. NS
Answer
septrum.org. 5 NS ns-716.awsdns-25.net.
septrum.org. 5 NS ns-782.awsdns-33.net.
septrum.org. 5 NS ns-1706.awsdns-21.co.uk.
septrum.org. 5 NS ns-560.awsdns-06.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0