nameserver2.punkt.de has no CNAME records.
Question and response
Question
dig nameserver2.punkt.de. NS
Answer
The response has no answer records.
Authority
punkt.de. 2783 SOA nameserver1.pluspunkthosting.de. hostmaster.punkt.de. 2026030301 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0