AutoResponse not delivered to some Customers

[robert_weber]

Auto-replies sent by OTRS at ticket opening time are emails without a "MAIL FROM" in the email envelope.
That is to say, these emails are normal in terms of display - they have a correct From field among other things.
But during the SMTP conversation, the MAIL FROM value of the email is empty. In other words, the email ENVELOPE has an empty sender.

Having an empty sender in the email envelope is a special case, dedicated to DSN emails (Delivery Status Notification, most of the time it is error messages.)

As a result, would anything go bad in the email sent by OTRS, no error is ever sent back to the sender (because there is no sender.)
The fact that the email displays a correct sender (because of a correct From or Sender header inside the email) doesn't help, as email headers are never used while routing the email. Only the email envelope is taken into account at routing time.

In addition, as these emails are special, in some cases they are processed a special way and the recipients don't receive them (if they are automatically deleted.)

These emails should be sent with a non-empty sender in the email envelope, so that they are plain, regular emails, processed normally at all stages from end to end.

Can somebody let me know, where I can configure this?
Or is this a very special bug?

Please let me know.

Many thanks in advance.

[jojo]

You can change this in Core::Sendmail.

Technical this behavour is correct and should prevent some loops or bounces on received spam