I have quite a few clients using iPhones of different IOS versions and my Exchange server is slowing down and the clients with iPhones complain that they are not getting their emails on time. Any thoughts?

Hi, Through testing determined the problem is related to changing the Primary email address on a users mailbox. Per Microsoft a GUID is assigned to the Primary email address and is used with ActiveSync. So even if you change the Primary email address back to the original email address it still has a new GUID. The resolution steps for this issue are: 1. First set the Primary email address of the users mailbox. 2. On the Mobile Device (MDA) open ActiveSync. Click Menu Options. Select the Exchange Server config then click Delete. This will remove the Server Source from ActiveSync. All your email will be removed from the Mobile device Calendar and Contacts will remain. 3. Then Click Menu Configure Server. Proceed with configuring your server options as you would when setting up a new user. On your first Sync you will get an error click Sync again and you will be prompted to accept the server policy settings just click ok. (we are pushing mobile device policies from the Exchange server) 4. Delete an email from your Mobile Device then Sync. Verify that the email is removed from mailbox in Outlook. I hope this will help you. Regards. Shafaquat Ali.M.C.I.T.P Exchange 2007/2010, M.C.I.T.P Windows Server 2008, M.C.T.S OCS Server 2007 R2, URL: http://blog.WhatDoUC.net Phone: +923008210320