Ich bekam heute bei dem Versuch eine Mail zu senden, vom Empfänger folgende Undeliverable Message zugestellt, der meine Mail wg Spam oder Virus ablehnte.

Undeliverable Message (gekürzt und anonymisiert)

Reporting-MTA: dns; mailout11.t-online.de Arrival-Date: Tue, 22 Jul 2025 10:46:23 +0200 (CEST) Final-Recipient: rfc822 Original-Recipient: rfc822 Action: failed Status: 5.7.1 Remote-MTA: dns; mx.xxxxxxx.cust.a.hostedemail.com Diagnostic-Code: smtp; 550 5.7.1 Message contains spam or virus. (109) [1753173984-332715]

(Ende Undelivable Message)

Der Test meiner Mailadresse unter mail-tester.com ergab, dass der Mailout-Server der Telekom in zwei Datenbanken, Backscatterer und Redhawk, blackgelistet ist. Als Beispiel füge ich den Backscatterer-Bericht ein.

Testresult for 194.25.134.82:

This IP IS CURRENTLY LISTED in our Database.
Please note that this listing does NOT mean you are a spammer, it means your mailsystem is either poorly configured or it is using abusive techniques.
This kind of abuse is known as BACKSCATTER (Misdirected Bounces or Misdirected Autoresponders or Sender Callouts). Click the links above to get clue how and why to stop that kind of abuse.


To track down what happened investigate your smtplogs near 18.07.2025 11:24 CEST +/-1 minute.

You will either find that your system tried to send misdirected bounces or misdirected autoresponders to claimed but in reality faked senders, or your system tried sender verify callouts against our members near that time.

So you should look for outgoing emails that have a NULL SENDER or POSTMASTER in MAIL FROM.

Reading your logs carefully it shouldn't be a big deal to figure out what caused or renewed your listing.

(Ende Testresult)

Das ist das erste Mal, dass ich diesem Empfänger keine Mail von meinem Konto zusenden kann.

Was kann hier getan werden, damit ich Mails an den Empfänger wieder zustellen kann?

Danke für die Aufmerksamkeit.