Issue: Calendar and contact items entered on an iOS device do not synchronize to Outlook or Outlook Web Access (OWA). However, similar items entered in Outlook or OWA DO synchronize with iOS.
Always verify that this is the issue by comparing items in Outlook Web Access with the iOS device, not Outlook. If items are synchronizing properly in OWA and the device, the issue is with the Outlook client.
Confirm that contacts are not set to save locally by default. This can be confirmed by going to Settings > Mail, Contacts, Calendars. Scroll down to the Contacts section. If there is a field called default account, make sure it is set to the Exchange account. Most likely it is set to on my iPhone. Existing local contacts cannot be modified to store them in the Exchange address book. They will need to be re-created on the device or the user will need to sync the device to Outlook using iTunes. This will create duplicates for the local contacts. The user will then need to go back and delete the original entry for each, or hide the contacts created locally to view Exchange contacts only. Follow the same procedure to set the default calendar to Exchange.
The same situation applies with the calendar. If the calendar is set to use anything but the Exchange calendar, new items will not synchronize to OWA. The setting for the default calendar can be found by scrolling to the bottom of the Mail, Contacts, Calendars screen.
To view Exchange contacts without local contacts on the iPhone or iPad, go to Contacts > Groups > tap Hide All Contacts, tap just the Contacts folder under Exchange, then tap Done. If All Contacts are selected, Suggested Contacts will be included and duplicates will likely be visible. If you have any other accounts with contacts, you can also check them here.