Apex domains cannot have CNAME records.
Question and response
Question
dig calabrio.com. NS
Answer
calabrio.com. 5 NS emma.ns.cloudflare.com.
calabrio.com. 5 NS simon.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0