Apex domains cannot have CNAME records.
Question and response
Question
dig medallia.com. NS
Answer
medallia.com. 5 NS ns-183.awsdns-22.com.
medallia.com. 5 NS ns-881.awsdns-46.net.
medallia.com. 5 NS ns-1363.awsdns-42.org.
medallia.com. 5 NS ns-1874.awsdns-42.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0