Apex domains cannot have CNAME records.
Question and response
Question
dig ca2.prodgdc.com. NS
Answer
ca2.prodgdc.com. 5 NS ns-1874.awsdns-42.co.uk.
ca2.prodgdc.com. 5 NS ns-261.awsdns-32.com.
ca2.prodgdc.com. 5 NS ns-749.awsdns-29.net.
ca2.prodgdc.com. 5 NS ns-1417.awsdns-49.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0