Apex domains cannot have CNAME records.
Question and response
Question
dig cj2.nl. NS
Answer
cj2.nl. 5 NS ns5.cj2.nl.
cj2.nl. 5 NS ns6.cj2.nl.
Authority
The response has no authority records.
Additional
ns5.cj2.nl. 5 A 94.124.88.54
ns6.cj2.nl. 5 A 46.182.218.144
ns5.cj2.nl. 5 AAAA 2a00:1bd0:0:140:94:124:88:54
ns6.cj2.nl. 5 AAAA 2a00:1bd0:0:9201:46:182:218:144
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0