Apex domains cannot have CNAME records.
Question and response
Question
dig isphost.net. NS
Answer
isphost.net. 5 NS ispns2.arvid.ee.
isphost.net. 5 NS ispns1.arvid.ee.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0