mail.noffer.de has no CNAME records.
Question and response
Question
dig mail.noffer.de. NS
Answer
The response has no answer records.
Authority
noffer.de. 150 SOA docks17.rzone.de. hostmaster.strato-rz.de. 2020050810 86400 7200 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0