Question forward mails get no error

[Oli_mt]

Hi,

I have a problem with forward mails.

Following example.

Email: test1@plesktest.abc (My adress in plesk)
Email: max@muster.abc (the forward adress insert in test1@plesktest.abc)
Email: sender@domain.abc (sender adress)

If I send a mail from sender@domain.abc to test1@plesktest.abc
Every thing is fine and max@muster.abc get the mail

But now if i change the adress max@muster.abc to max1@muster.abc (no existing adresse)
and i send mail to test1@plesktest.abc the sender sender@domain.abc get no error mail
like

Mail delivery failed: returning message to sender
This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

test1@plesktest.abc
host mail.plesktest.abc [xxx.xxx.xxx.xxx]
SMTP error from remote mail server after RCPT TO:<test1@plesktest.abc>:
550 5.1.1 <test1@plesktest.abc>: Recipient address rejected:
User unknown in virtual mailbox table


Please can you help me ?!

Regards
Oliver

Plesk Version 17.5.3 Update #43