Apex domains cannot have CNAME records.
Question and response
Question
dig stepstone.com. NS
Answer
stepstone.com. 2 NS ns.domainnetwork.se.
stepstone.com. 2 NS ns2.domainnetwork.se.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0