Minus sign in notification bar
If you are seeing minus or negative sign in status bar, this minus sign could be arrow shaped, rounded or square, this is actually a symbol that your notifications has been disabled.
as i wrote earlier it is because you have disabled notifications, so all you have to do is enable notifications, just drag status bar down and swipe to left and tap on notification icon, as shown in image below
And you are done. as you can see minus sign has been vanished.