If the page is unable to access https://ajax.googleapis.com then the page may not load correctly. To test this add https://ajax.googleapis.com to the Local Intranet zone or the Trusted sites zone under ‘Internet Options’ and the ‘Security’ tab, then refresh your browser and the page should load correctly.
Update: In version 3.0 and higher there is an option on the admin page to enable ‘Local JQuery and Fonts’, this prevents the phonebook from connecting to external URLs.
