Apex domains cannot have CNAME records.
Question and response
Question
dig leonix.net. NS
Answer
leonix.net. 5 NS ns4.leonix.fr.
leonix.net. 5 NS ns3.leonix.fr.
leonix.net. 5 NS ns1.leonix.fr.
leonix.net. 5 NS ns2.leonix.fr.
Authority
The response has no authority records.
Additional
ns1.leonix.fr. 5 A 185.173.68.59
ns2.leonix.fr. 5 A 185.173.68.60
ns3.leonix.fr. 5 A 79.137.34.228
ns4.leonix.fr. 5 A 51.15.223.200
ns3.leonix.fr. 5 AAAA 2001:41d0:302:2200:0:0:0:42a
ns4.leonix.fr. 5 AAAA 2001:bc8:654:1427:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0