Apex domains cannot have CNAME records.
Question and response
Question
dig samanage.com. NS
Answer
samanage.com. 5 NS ns-1029.awsdns-00.org.
samanage.com. 5 NS ns-1914.awsdns-47.co.uk.
samanage.com. 5 NS ns-110.awsdns-13.com.
samanage.com. 5 NS ns-820.awsdns-38.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0