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