mx.converia.de has no CNAME records.
Question and response
Question
dig mx.converia.de. NS
Answer
The response has no answer records.
Authority
converia.de. 434 SOA nsa9.schlundtech.de. info.converia.de. 2025111908 43200 7200 1209600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0