Unsollicited Bulk Email

[Erik Kramer]

Hi,

I run a multi domain mail server (Kolab 3.4).

And since yesterday my users receive a message like below, when sending a
message.

Any ideas on how to fix it?

Thanks for your help,


Erik


A message from <XXXX>
to: XXXX

was considered unsolicited bulk e-mail (UBE).

Our internal reference code for your message is 02611-06/Wb81Bb8nbs25

The message carried your return address, so it was either a genuine mail
from you, or a sender address was faked and your e-mail address abused
by third party, in which case we apologize for undesired notification.

We do try to minimize backscatter for more prominent cases of UBE and
for infected mail, but for less obvious cases some balance between
losing genuine mail and sending undesired backscatter is sought,
and there can be some collateral damage on either side.

First upstream SMTP client IP address: [XXX.XXX.XXX]

Return-Path: XXXX
From: XXXX
Sender: XXXXX
Message-ID: XXXXXX

Delivery of the email was stopped!
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