Apex domains cannot have CNAME records.
Question and response
Question
dig fi.cloudplatform.fi. NS
Answer
fi.cloudplatform.fi. 5 NS ns27.fi.cloudplatform.fi.
fi.cloudplatform.fi. 5 NS ns26.fi.cloudplatform.fi.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0