[StAPF] Delivery Status Notification (Failure)

The following message to <atheurich(a)rauheshaus.de&gt; was undeliverable. The reason for the problem: 5.1.0 - Unknown address error 554-'5.7.1 <atheurich(a)rauheshaus.de&gt;: Recipient address rejected: Rejected by SPF: 129.206.100.212 is not a designated mailserver for stapf%40zapf.in (context mfrom, on eckdmx04.eckd.de)'