Apex domains cannot have CNAME records.
Question and response
Question
dig blackberry.com. NS
Answer
blackberry.com. 5 NS ns-1097.awsdns-09.org.
blackberry.com. 5 NS ns-249.awsdns-31.com.
blackberry.com. 5 NS ns-770.awsdns-32.net.
blackberry.com. 5 NS ns-1561.awsdns-03.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0