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