Board Thread:Questions and Answers/@comment-99.90.67.63-20150430201625/@comment-26044650-20150430212315

You need to add friends in the LINE app before you can invite them in your games.

If you've done that, try restarting your game. Double tap your home button, swipe left/right until you find the app and swipe it upward to close it. Then open it.

It will force the sever to sync up and give you a list of friends you can invite.