Hi

One of my users sent an email to an invalid account on our domain. Not a problem, these things happen, except the bounce he got was incomplete:

HTML Code:
This is the mail system at host my.domain.com.

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

<bogusaddress@domain.com>: domain.com
And that is all. I would expect to see the reason for the bounce. I have tried from internally and externally and I see the same thing.

Anyone know what might be causing this or where I should start digging?

Thanks
Simon