I have trouble of adding a specific user as friend:
Star_S (1301480)
We both can’t see each other in the friends list (including offline), and the notification inbox is empty. But when one of us trying to click the “Add Friend” button, there is a popup says that “Already invited to be your friend” and nothing happens.
Did you both send friend requests and cleared all notifications? Clearing a notification is equivalent to refusing a friend request, and once cleared, it’s lost and you can’t be invited again.