Apex domains cannot have CNAME records.
Question and response
Question
dig sentry-eds.com. NS
Answer
sentry-eds.com. 5 NS ns-80.awsdns-10.com.
sentry-eds.com. 5 NS ns-1301.awsdns-34.org.
sentry-eds.com. 5 NS ns-760.awsdns-31.net.
sentry-eds.com. 5 NS ns-1586.awsdns-06.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0