Apex domains cannot have CNAME records.
Question and response
Question
dig cloud.coop. NS
Answer
cloud.coop. 2 NS ns-1528.awsdns-63.org.
cloud.coop. 2 NS ns-1882.awsdns-43.co.uk.
cloud.coop. 2 NS ns-43.awsdns-05.com.
cloud.coop. 2 NS ns-864.awsdns-44.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0