Apex domains cannot have CNAME records.
Question and response
Question
dig ess.ca.barracuda.com. NS
Answer
ess.ca.barracuda.com. 5 NS ns-1497.awsdns-59.org.
ess.ca.barracuda.com. 5 NS ns-286.awsdns-35.com.
ess.ca.barracuda.com. 5 NS ns-565.awsdns-06.net.
ess.ca.barracuda.com. 5 NS ns-1795.awsdns-32.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0