I've recently noticed the following Error in my Server logs. Happens whenever Mobile device user attempts to syncrhonise using OMA. The error is logged on the server, but the user is able to sync, albeit slowly.
Event Type: Error Event Source: Server ActiveSync Event Category: None Event ID: 3005 Date: 16/03/2010 Time: 01:22:20 PM User: xxxxxx Computer: xxxxxx Description: Unexpected Exchange mailbox Server error: Server: xxxxxx User: xxxxxx HTTP status code: . Verify that the Exchange mailbox Server is working correctly.