Hallo Coole Katze,

hier die Daten:
-----Ursprüngliche Nachricht-----
From: Mail Delivery System
Sent: Monday, July 27, 2020 8:45 PM
To:
Subject: Undelivered Mail Returned to Sender

This is the mail system at host mailout01.t-online.de.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<@live.de>: host eur.olc.protection.outlook.com[104.47.14.33] said:
550 5.7.1 Unfortunately, messages from [194.25.134.80] weren't sent. Please
contact your Internet service provider since part of their network is on
our block list (S3140). You can also refer your provider to
http://mail.live.com/mail/troubleshooting.aspx#errors.
[VI1EUR04FT023.eop-eur04.prod.protection.outlook.com] (in reply to MAIL
FROM command)

<@gmx.net>: host mx01.emig.gmx.net[212.227.17.5] said: 554-Transaction
failed 554-Reject due to policy restrictions. 554 For explanation visit
https://www.gmx.net/mail/senderguidelines?ip=194.25.134.80&c=hi (in reply
to end of DATA command)

<@gmx.de>: host mx01.emig.gmx.net[212.227.17.5] said: 554-Transaction
failed 554-Reject due to policy restrictions. 554 For explanation visit
https://www.gmx.net/mail/senderguidelines?ip=194.25.134.80&c=hi (in reply
to end of DATA command)

<@gmx.de>: host mx01.emig.gmx.net[212.227.17.5] said: 554-Transaction
failed 554-Reject due to policy restrictions. 554 For explanation visit
https://www.gmx.net/mail/senderguidelines?ip=194.25.134.80&c=hi (in reply
to end of DATA command)

<@web.de>: host mx-ha03.web.de[212.227.15.17] said: 554-Transaction
failed 554-Reject due to policy restrictions. 554 For explanation visit
https://web.de/email/senderguidelines?ip=194.25.134.80&c=hi (in reply to
end of DATA command)

<@web.de>: host mx-ha03.web.de[212.227.15.17] said: 554-Transaction
failed 554-Reject due to policy restrictions. 554 For explanation visit
https://web.de/email/senderguidelines?ip=194.25.134.80&c=hi (in reply to
end of DATA command)

<@web.de>: host mx-ha03.web.de[212.227.15.17] said: 554-Transaction
failed 554-Reject due to policy restrictions. 554 For explanation visit
https://web.de/email/senderguidelines?ip=194.25.134.80&c=hi (in reply to
end of DATA command)

<@freenet.de>: host emig.freenet.de[195.4.92.218] said: 550 X-Warning:
Syntax error in header (in reply to end of DATA command)

<@freenet.de>: host emig.freenet.de[195.4.92.218] said: 550 X-Warning:
Syntax error in header (in reply to end of DATA command)

Return-Path: <@t-online.de>
Received: from fwd15.aul.t-online.de (fwd15.aul.t-online.de [172.20.27.63])
by mailout01.t-online.de (Postfix) with SMTP id 062794289409;
Mon, 27 Jul 2020 20:44:58 +0200 (CEST)
Received: from mkHP .t-online.de
with (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384 encrypted)
esmtp id 1k087N-2ctHDk0; Mon, 27 Jul 2020 20:44:57 +0200
Message-ID: <9E38B5AF68E1449F8AB20B9BE2FE8789@mkHP>
From: ">
To: <Undisclosed-Recipient:;>
Subject:
Date: Mon, 27 Jul 2020 20:44:55 +0200
MIME-Version: 1.0
Content-Type: multipart/related;
type="multipart/alternative";
boundary="----=_NextPart_000_005A_01D66456.C91E9CC0"
X-Priority: 3
X-MSMail-Priority: Normal
Importance: Normal
X-Mailer: Microsoft Windows Live Mail 16.4.3528.331
X-MimeOLE: Produced By Microsoft MimeOLE V16.4.3528.331
X-ID: r3SnNcZYZhfvOZGxDjnxK+OcgD+GAg2pUYi1iLgY3SICK-t+kXF4Sa-uBaNFvEJwB-
X-TOI-EXPURGATEID: 150726::1595875497-0000E7A1-B31FB9B3/0/0 CLEAN NORMAL
X-TOI-MSGID: b8f3aa2a-78d8-438e-a118-7b2d6f0eec58

Nach weiterer Suche bin ich im David Mailserver Forum darauf gestoßen das es wohl notwendig ist nicht nur das BCC Feld mit Adressaten zu befüllen sondern auch im An Feld muss ein Empfänger stehen, sonst wird die Mail wohl abgelehnt.

Vielen Dank hier an Alle die helfen wollten.

Hallo @vinnylan ,

vielen Dank für die Rückmeldung, ich hatte gerade heute morgen schon versucht rauszufinden, was die "policy restrictions" bei gmx und web.de sind. Und über die Links kam nichts als gesperrt raus. Das erklärt es jetzt,

Danke,

Coole Katze