mail4.epag.de has no MX records.
Question and response
Question
dig mail4.epag.de. MX
Answer
The response has no answer records.
Authority
epag.de. 300 SOA dns1.epag.net. support.epag.de. 1772006186 10800 3600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0