Group Invite All is extension which used to add all your friends in facebook group by single click.
Everything working find, if sometime not working then please reload the page and try again.
VERSION 3.4.1 ****
-- Bug Fix and Speed Improvements
-- Now you can set the limit of adding friends from option page (Already adding members does not count in adding limit)
To use this extension open the facebook group page and click on extension icon inside the address bar.
-- If you have any problem please send me a screenshot of your problem at my email : firstname.lastname@example.org or contact us on my facebook page https://www.facebook.com/offical.softarea