Apex domains cannot have CNAME records.
Question and response
Question
dig 0ns.eu. NS
Answer
0ns.eu. 5 NS a.0ns.eu.
0ns.eu. 5 NS c.0ns.eu.
0ns.eu. 5 NS b.0ns.eu.
Authority
The response has no authority records.
Additional
a.0ns.eu. 5 A 195.88.5.1
b.0ns.eu. 5 A 162.250.147.7
c.0ns.eu. 5 A 185.136.176.100
a.0ns.eu. 5 AAAA 2a00:dcc0:eda:2:195:88:5:1
b.0ns.eu. 5 AAAA 2a00:dcc7:d3ff:0:162:250:147:7
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0