Apex domains cannot have CNAME records.
Question and response
Question
dig ripe.as60456.net. NS
Answer
ripe.as60456.net. 2 NS srv-web-kt001.2idm.com.
ripe.as60456.net. 2 NS srv-web-kt003.2idm.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0