hostonserver.de has no MX records.
Question and response
Question
dig hostonserver.de. MX
Answer
The response has no answer records.
Authority
hostonserver.de. 86400 SOA alpha.host-on.net. do-not-reply.hostonserver.de. 2026021600 43200 7200 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0