auth02.dns.trueserver.nl has no NS records.
NS records for this zone are defined at trueserver.nl.
NS records for this zone are defined at trueserver.nl.
Question and response
Question
dig auth02.dns.trueserver.nl. NS
Answer
The response has no answer records.
Authority
trueserver.nl. 86400 SOA auth01.dns.trueserver.nl. hostmaster.trueserver.nl. 2017060616 86400 3600 604800 86400
Additional
. 0 OPT ; payload 1400, xrcode 0, version 0, flags 0