hosted.mailcow.de has no CNAME records.
Question and response
Question
dig hosted.mailcow.de. NS
Answer
The response has no answer records.
Authority
mailcow.de. 3152 SOA angus.ns.servercow.de. hostmaster.servercow.de. 2026030501 14400 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0