We recently made changes to our Exchange environment in preparation for our move to Exchange 2010. We have reports of some Android phones not being able to sync to Exchange 2007. We have used this solution to reinstate synchronization with affected Android devices, though this solution should work with other Active Sync devices as well.
Step 1) Login to your email account at webmail.unt.edu.
Step 2) Click options in the uppoer right hand corner of the screen.
Step 3) Select Mobile Device from the menu on the left.
Step 4) Remove your device from the list of Active Sync device.
Note: If you have more than one listing, choose the setting with the most recent sync date and time.
Step 5) Click Save at the bottom of the page.
Step 6) On your Android, make sure that legacy.unt.edu is entered as your mail server.
Step 7) Re-sync your device.
If after you migrated to Exchange 2010 and still not being able to sync your email even you had changed the server setting on your device to webmail.unt.edu. Please use the following solution to reinstate synchronization, though this solution should work with other Active Sync devices as well.
Step 1) Login to your email account at webmail.unt.edu.
Step 2) Click options in the upper right hand corner of the screen.
Step 3) Select See All Options from the pull down menu.
Step 4) Click on the Phone on the left pane.
Step 5) Select the Mobile Phones on top of the screen
Step 6) Highlight your device and click the "X" icon to remove your device from the list of Active Sync device.
Note: If you have more than one listing, choose the setting with the most recent sync date and time.
Step 7) Click Yes to confirm the delete screen.
Step 8) On your Android, make sure that webmail.unt.edu is entered as your mail server. (or autodiscover.unt.edu should works too for some user)
Step 9) Re-sync your device. Remember, you might wait a few minutes and try again for the system to replicate/clean out the deleted device
Step 10) (optional) Re-boot your device by turning off and turning back on your device and re-sync.