There's an event in the Application Log for ActiveSync - ID 3033.
Following this article:
I checked the suggested registry key...
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MasSync\ParametersAnd all four DWORDs are missing... I have set them to:
- MinHeartbeatInterval - Dword - Decimal 60 (seconds)
- MaxHeartbeatInterval - Dword - Decimal 2700 (seconds)
- HbiSampleSize - Dword - Decimal 200 (samples)
- HbiAlertThreshold - Dword - Decimal 480 (seconds)
It suggests changing the HTTP(S) timeout values on the router firewall but I can't find them... so I'm going to do a simple IISRESET and see if that resolves the problem. Trouble is, an IISRESET might just resolve the issue, despite the new registry entries... so I can only warn the client that's a possibility... (when he returns)...
If that doesn't resolve the issue for now... back to the drawing board...