firm239.e.teqbow.de.com has no CNAME records.
Question and response
Question
dig firm239.e.teqbow.de.com. NS
Answer
The response has no answer records.
Authority
teqbow.de.com. 834 SOA dns1.registrar-servers.com. hostmaster.registrar-servers.com. 1770918773 43200 3600 604800 3601
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0