Apex domains cannot have CNAME records.
Question and response
Question
dig redflush.eu. NS
Answer
redflush.eu. 5 NS ns2.dnsoperations.net.
redflush.eu. 5 NS ns3.dnsoperations.net.
redflush.eu. 5 NS ns1.dnsoperations.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0