pdns2.test.server.csl.de has no NS records.
NS records for this zone are defined at csl.de.
NS records for this zone are defined at csl.de.
Question and response
Question
dig pdns2.test.server.csl.de. NS
Answer
The response has no answer records.
Authority
csl.de. 300 SOA a.ns.nrw.net. hostmaster.joker.com. 2026030348 14400 3600 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0