zeus.f5s.de has no MX records.
Question and response
Question
dig zeus.f5s.de. MX
Answer
The response has no answer records.
Authority
f5s.de. 3600 SOA ns.inwx.de. hostmaster.fuchsi.de. 2026011700 10800 3600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0