PureMessage Blocking Valid Message, "Invalid Recipients"

Question

Sophos is blocking a valid inbout email but only blocking it for some recipients, in the Acvitiy Monitor only we see the error: Blocked Message '<---@domain>' for invalid recipients 'example@.com....'

When looking at who should be receiving the email, the first seven recipients receive the email ok, but after that everyone else is blocked.

The message does not get quarantined and does not appear in any other Sophos log. It does however appear in the Exchange Message Tracking log with an error of FAIL and pme12transport.

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mbjoe · Accepted Answer

I ended up talking to tech support to find a solution, but it is a known bug in PureMessage that they hope to fix with the next update. The problem occurs when sending/receiving a message with 15 or more recipients. We noticed that each time a message was sent with more then 15, the last 15 recipients would not receive the message while the rest would. So if you sent to 20 people, the first 5 would recieve the email and the last 15 wouldn't. If you send to 21, the first 6 would receive the message and the remaining 15 wouldn't. So tech support basically said we had to turn off the Validation Filter until the update is released. :10077