Cause:
This issue occurs when the host doesn't have Webex Personal Conference (AUO) privileges enabled for their account.

Solution:

Site Administrators only

To resolve the issue:

1. Log in to your Cisco Webex Meetings Site Administration  page. (Example: SITENAME.webex.com/admin.php)
2. Click on Users > Edit Users in the left panel.
3. Enter search criteria for the host into the User name: or Email: field, then click the Search button.
4. Click on the name of the account you would like to modify.
5. Scroll down to the Privileges: section:
    
     
6. Check the AUO: Webex Personal Conference box.
7. Scroll to the bottom of the page, then click the Update button.
    
   After enabling the Webex Personal Conference service for the host, the host will need to refresh their Webex Desktop App settings.

To refresh Webex Desktop App settings:

1. Go to Start > All Programs > Webex > Webex Desktop App > Webex Settings.
   
   The 'Webex Settings' window appears.
    
2. Click the OK button.
    
   The Add Personal Conference Meeting option will now be available on the Outlook New Appointment window.