Apex domains cannot have CNAME records.
Question and response
Question
dig mailblaze.com. NS
Answer
mailblaze.com. 4 NS harmony.ns.cloudflare.com.
mailblaze.com. 4 NS cris.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0