Apex domains cannot have CNAME records.
Question and response
Question
dig statuspage.io. NS
Answer
statuspage.io. 5 NS ns-209.awsdns-26.com.
statuspage.io. 5 NS ns-1560.awsdns-03.co.uk.
statuspage.io. 5 NS ns-1407.awsdns-47.org.
statuspage.io. 5 NS ns-951.awsdns-54.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0