Apex domains cannot have CNAME records.
Question and response
Question
dig ankh.fr.eu.org. NS
Answer
ankh.fr.eu.org. 5 NS kell-vultr.ankh.fr.eu.org.
ankh.fr.eu.org. 5 NS gchq.fdn.fr.
ankh.fr.eu.org. 5 NS nsa.fdn.fr.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0