Apex domains cannot have CNAME records.
Question and response
Question
dig w2-3.abo.wanadoo.fr. NS
Answer
w2-3.abo.wanadoo.fr. 5 NS ns4.orange.fr.
w2-3.abo.wanadoo.fr. 5 NS ns1.orange.fr.
w2-3.abo.wanadoo.fr. 5 NS ns2.orange.fr.
w2-3.abo.wanadoo.fr. 5 NS ns3.orange.fr.
Authority
The response has no authority records.
Additional
ns1.orange.fr. 2 A 80.10.201.224
ns2.orange.fr. 2 A 80.10.202.224
ns3.orange.fr. 2 A 80.10.200.224
ns4.orange.fr. 2 A 80.10.203.224
ns1.orange.fr. 2 AAAA 2a01:cb04:2040:2:0:0:0:1
ns2.orange.fr. 2 AAAA 2a01:cb09:2040:6:0:0:0:1
ns3.orange.fr. 2 AAAA 2a01:cb04:2040:2:0:0:0:1
ns4.orange.fr. 2 AAAA 2a01:cb09:2040:6:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0