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