You might have to go to the Midi Control Center and set the Pitch bend midi channel. It might have gone off the deep end. Of course, it depends if you're using an Arturia midi keyboard controller. If you're using another product, you'd have to use their software to reprogram whatever you're using. If, on the other hand, you're using a mouse, then the obvious answer would be to un-install AL4 then reinstall it.