ns1.nsserve.de has no CNAME records.
Question and response
Question
dig ns1.nsserve.de. NS
Answer
The response has no answer records.
Authority
de. 3600 SOA f.nic.de. dns-operations.denic.de. 1773100757 7200 7200 3600000 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0