mta00.he-roes.de has no MX records.
Question and response
Question
dig mta00.he-roes.de. MX
Answer
The response has no answer records.
Authority
he-roes.de. 300 SOA ns1031.ui-dns.com. hostmaster.1and1.com. 2017060688 28800 7200 604800 300
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0