Recipient address rejected: User unknown in virtual mailbox table

[Darkcallen]

Ladies and Gentlemen
we have a RootServer Hetzner with Plesk 11
There we have installed over the panel postfix.
Then created a customer, there entered a domain.
Then email Dressen created.
This email can be accessed with Outlook.
Email to come it works super.
But sending email via this is not possible.
It comes back the following email:

Your message did not reach some or all recipients.

Subject: test
Posted on: 02.08.2013 18:34

The following recipient (s) can / can not be reached:

'xxxx@xxxx.de' on 02.08.2013 18:34
Server Error: "550 5.1.1 <xxxx@xxxx.de>: Recipient address rejected: User unknown in virtual mailbox table" '

How can we correct the problem?

Sincerely yours

Dennis Schläger

 

[InderS]

have you checked : http://kb.parallels.com/en/6440