Apex domains cannot have CNAME records.
Question and response
Question
dig scaleway.com. NS
Answer
scaleway.com. 1 NS nsd.scaleway.com.
scaleway.com. 1 NS nsa.scaleway.com.
scaleway.com. 1 NS nsb.scaleway.com.
scaleway.com. 1 NS nsc.scaleway.com.
Authority
The response has no authority records.
Additional
nsa.scaleway.com. 1 A 51.159.69.138
nsb.scaleway.com. 1 A 51.159.47.9
nsc.scaleway.com. 1 A 51.158.139.22
nsd.scaleway.com. 1 A 151.115.8.9
nsa.scaleway.com. 1 AAAA 2001:bc8:808:1:0:0:0:9
nsb.scaleway.com. 1 AAAA 2001:bc8:808:1:0:0:0:7
nsc.scaleway.com. 1 AAAA 2001:bc8:5008:200:0:0:0:9
nsd.scaleway.com. 1 AAAA 2001:bc8:1c08:100:0:0:0:6
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0