mail.rx.databay.de has no CNAME records.
Question and response
Question
dig mail.rx.databay.de. NS
Answer
The response has no answer records.
Authority
rx.databay.de. 334 SOA ns.databay.de. hostmaster.databay.de. 2026021901 86400 14400 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0