Apex domains cannot have CNAME records.
Question and response
Question
dig openlearningcanada.com. NS
Answer
openlearningcanada.com. 5 NS ns-1860.awsdns-40.co.uk.
openlearningcanada.com. 5 NS ns-411.awsdns-51.com.
openlearningcanada.com. 5 NS ns-1242.awsdns-27.org.
openlearningcanada.com. 5 NS ns-1633.awsdns-12.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0