After the new game update (version 2.7) there is a bug during the invitation procedure.
When you press the button to invite a new neighbor, you see the processing icon for 2-3 seconds and then the game crashes before the message "SUCCESS! You invited XXX to be your neighbor" appears.
The neighbor has been invited instead, but every time you go to the invite tab again (Menu -> Social -> Invite) the game crashes immediately and you can't invite anyone else.
The bug exists on the iOS platforms only and not on the Android ones.
P.S. New players or Low Level ones that have island goals to invite new neighbors, can't fulfill them, even if the first invitation is sending successfully, just before the crash.