You need to update your Outlook address book from Exchange server
1. Select the Send/Receive tab in the upper left corner of Outlook.
2. Click on the Send/Receive Groups drop down menu, then Download Address Book…
3. The Offline Address Book window will appear. Make sure the following options are selected:
– De-check the Download changes since last Send/Receive option
– Make sure the \Global Address List is selected from the Choose address book drop down menu
– Click the OK button at the bottom.
4. The most recent version of the Global Address List will be downloaded.
5. Close Outlook when the download has finished. Re-open Outlook and log in; the Global Address List should now contain the most recent information.