Apex domains cannot have CNAME records.
Question and response
Question
dig whitelabelserver.nl. NS
Answer
whitelabelserver.nl. 5 NS ns1.whitelabelserver.nl.
whitelabelserver.nl. 5 NS ns2.whitelabelserver.nl.
whitelabelserver.nl. 5 NS ns3.whitelabelserver.nl.
Authority
The response has no authority records.
Additional
ns1.whitelabelserver.nl. 5 A 178.21.19.10
ns2.whitelabelserver.nl. 5 A 46.249.42.58
ns3.whitelabelserver.nl. 5 A 23.88.104.32
ns1.whitelabelserver.nl. 5 AAAA 2a00:1ca8:2:0:0:0:0:10
ns2.whitelabelserver.nl. 5 AAAA 2a03:3f40:e:0:0:0:0:10
ns3.whitelabelserver.nl. 5 AAAA 2a01:4f8:1c1b:df07:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0