If the +1 button is unavailable or has stopped working, you'll see this image:

A +1 button error can occur for a variety of reasons, including the following:

• Server timeout: Check your Internet connection and try refreshing the page.
• Suspended profile: If your profile has been suspended, you won't be able to +1 content.
• Apps user: Google profiles aren't available for Apps accounts, so you won't be able to use the +1 button.
• Blocked cookies: If you've disabled 3rd party cookies in your browser you won't be able to use the +1 button.