mx.tgos.de has no NS records.
NS records for this zone are defined at tgos.de.
NS records for this zone are defined at tgos.de.
Question and response
Question
dig mx.tgos.de. NS
Answer
The response has no answer records.
Authority
tgos.de. 900 SOA ns1.plusserver.com. hostmaster.plusserver.com. 2025041105 1800 900 604800 900
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0