ns3.asok.de has no CNAME records.
Question and response
Question
dig ns3.asok.de. NS
Answer
The response has no answer records.
Authority
asok.de. 1850 SOA ns1.asok.de. hostmaster.asok.de. 8 86400 10800 3600000 172800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0