Our environment is Active Directory 2003, Exchange 2003, with a mix of 2003, 2008 R2 servers.

The only thing from the exchange side that does not work is Active-Sync with mobile phones. OWA is working fine (very responsive). When I enable Outlook Mobile access and unsupported devices, I am able to successfuly browse to www.mail.site/oma it allows me to see inbox, calendar, etc. By default we had it historically disabled. Whether we have it on or off does not seem to make any difference.

We are seeing alot of Application event log entries on the Front End server where

Source: Server ActiveSync Event ID: 3005

Unexpected Exchange mailbox Server error: Server: [mailserver.domain.com] User: [username@domain.com] HTTP status code: [507]. Verify that the Exchange mailbox Server is working correctly.

AND Source: Server ActiveSync Event ID: 3007

Exchange mailbox Server response timeout: Server: [mailserver.domain.com] User: [username@domain.com]. Exchange ActiveSync Server failed to communicate with the Exchange mailbox server in a timely manner. Verify that the Exchange mailbox Server is working correctly and is not overloaded.

We have rebooted the Front End server, our mailserver is clustered so when we rebooted the active node, the other one is now active and still nothing.

The intermittent issue comes in that for some users, manually syncing on the mobile email clients then proceeds to sync. For others, syncing just hangs up. This is impacting the entire organization.

When we run Remote Connectivity Analyzer, it sometimes works, sometimes fails on FolderSync Command, sometimes fails on other tests under the An ActiveSync session is being attempted with the server.

Any help would be appreciated and thanks in advance.

1 Answer 1


Solved: Hopefully this will help folks out. Root cause was a malformed email that was taking a long time to open in Outlook client itself. On the IIS Manager, we noticed that ExchangeApplictionPool -> Properties ->Health (tab) had Enable rapid-file protection checked. Our failures were set to 5. Increasing this value solved the problem since less then 10 people received this email. We then had users delete this email from their inbox.

What we think happened is that when the email was sent, the users were syncing with their mobile phones, and a denial of service occurred.

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