Apex domains cannot have CNAME records.
Question and response
Question
dig serverpronto.com. NS
Answer
serverpronto.com. 3 NS everton.ns.cloudflare.com.
serverpronto.com. 3 NS kenia.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0