[VOPmail Beta] user unknown

[Bill Rakowitz]

Title: Message

Hi all,   We run Modus with spam and sieve filtering.   In the middle of last week, we started getting calls that emails from a neighboring ISP are returning "user unknown" messages when sent to our system.   I have an account on the neighbors system, and can recreate the problem.  Some messages will deliver, but a very small percentage.   To our knowledge, this is only happening when messages are from this specific system.   The user accounts messages are being sent to are valid and receiving messages from other systems and the user accounts are verified against  VOPRadius.   I am not able to find any reference to these delivery failures in the error log.   Does anyone have an idea of where to look next?   Bill Rakowitz YK Communications