Apex domains cannot have CNAME records.
Question and response
Question
dig bb.nextpertise.nl. NS
Answer
bb.nextpertise.nl. 4 NS ns2.dnszones.nl.
bb.nextpertise.nl. 4 NS ns1.dnszones.eu.
bb.nextpertise.nl. 4 NS ns3.dnszones.be.
Authority
The response has no authority records.
Additional
ns1.dnszones.eu. 4 A 192.174.68.100
ns2.dnszones.nl. 4 A 176.97.158.100
ns3.dnszones.be. 4 A 77.73.231.203
ns1.dnszones.eu. 4 AAAA 2001:67c:1bc:0:0:0:0:100
ns2.dnszones.nl. 4 AAAA 2001:67c:10b8:0:0:0:0:100
ns3.dnszones.be. 4 AAAA 2a02:690:f:f:0:0:0:158
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0