Apex domains cannot have CNAME records.
Question and response
Question
dig groupenomotech.eu. NS
Answer
groupenomotech.eu. 5 NS a.dns.gandi.net.
groupenomotech.eu. 5 NS b.dns.gandi.net.
groupenomotech.eu. 5 NS c.dns.gandi.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0