We have all incoming email scanned Trend Micro Hosted Email Security - an external server.
However we seem to be getting a proportion of messages that get through Trend's email scanning host and then get bounced as spam by content filtering in Microsoft Exchange.
None of the emails I've checked so far are spam i.e. they are all valid.
The obvious solution that occurs to me is to get Microsoft Exchange to 'trust' Trend's email servers and ensure that all emails scanned by the Trend servers are marked as 'safe' by Microsoft Exchange.
Can this be done ? If so how do I do it ?