mail.kwberlin.com has no NS records.
NS records for this zone are defined at kwberlin.com.
NS records for this zone are defined at kwberlin.com.
Question and response
Question
dig mail.kwberlin.com. NS
Answer
The response has no answer records.
Authority
kwberlin.com. 300 SOA ns1.first-ns.de. sys\.dolores.kwberlin.com. 2026022402 3600 900 1209600 10800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0