Apex domains cannot have CNAME records.
Question and response
Question
dig orchid.atmailcloud.com. NS
Answer
orchid.atmailcloud.com. 5 NS ns-133.awsdns-16.com.
orchid.atmailcloud.com. 5 NS ns-1903.awsdns-45.co.uk.
orchid.atmailcloud.com. 5 NS ns-1033.awsdns-01.org.
orchid.atmailcloud.com. 5 NS ns-782.awsdns-33.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0