- Check the Outlook client and Outlook Web Access
- Verify the Outlook client is connected to Microsoft Exchange server
- Try searching in Outlook Web Access using a web browser
- Check/Udpate the configuration of Outlook client
- ie. verify appropriate mailbox is checked
- Verify basic connectivity
- Ensure DNS is set up and working properly
- Check the speed and reliability of the active network connection
- Verify server address
- Double check the server address is correct via Exchange System Manager
