Apex domains cannot have CNAME records.
Question and response
Question
dig uniserver.nl. NS
Answer
uniserver.nl. 5 NS ns3.uniserver.nl.
uniserver.nl. 5 NS ns2.uniserver.nl.
uniserver.nl. 5 NS ns1.uniserver.nl.
Authority
The response has no authority records.
Additional
ns1.uniserver.nl. 5 A 195.69.75.3
ns2.uniserver.nl. 5 A 195.69.75.10
ns3.uniserver.nl. 5 A 83.143.187.129
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0