Apex domains cannot have CNAME records.
Question and response
Question
dig ovh.com. NS
Answer
ovh.com. 5 NS dns200.anycast.me.
ovh.com. 5 NS dns.ovh.net.
ovh.com. 5 NS dns10.ovh.net.
ovh.com. 5 NS ns.ovh.net.
ovh.com. 5 NS ns10.ovh.net.
ovh.com. 5 NS ns200.anycast.me.
Authority
The response has no authority records.
Additional
ns10.ovh.net. 5 A 5.39.20.253
dns10.ovh.net. 5 A 5.135.85.109
ns10.ovh.net. 5 AAAA 2001:41d0:b00:3a00:0:0:0:2
dns10.ovh.net. 5 AAAA 2001:41d0:d00:6100:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0