Apex domains cannot have CNAME records.
Question and response
Question
dig btcloud.systems. NS
Answer
btcloud.systems. 2 NS gracie.ns.cloudflare.com.
btcloud.systems. 2 NS eric.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0