Apex domains cannot have CNAME records.
Question and response
Question
dig astra-dev.online. NS
Answer
astra-dev.online. 5 NS grannbo.ns.cloudflare.com.
astra-dev.online. 5 NS ganz.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0