mail.syzygy.de has no MX records.
Question and response
Question
dig mail.syzygy.de. MX
Answer
The response has no answer records.
Authority
syzygy.de. 7200 SOA ns2.syzygy.de. hostmaster.syzygy.de. 2901124807 10800 1800 1209600 7200
Additional
. 0 OPT ; payload 4000, xrcode 0, version 0, flags 0