Apex domains cannot have CNAME records.
Question and response
Question
dig serve-hosting.net. NS
Answer
serve-hosting.net. 5 NS linus.ns.1-grid.co.za.
serve-hosting.net. 5 NS linus.ns.1-grid.com.
serve-hosting.net. 5 NS linus.ns.1-grid.net.
serve-hosting.net. 5 NS linus.ns.1-grid.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0