this may sound stupid, but if your using a bar mod, make sure the binding for the key you wanting to press is setup to the correct bind.

i laid out all my bars the same and it didnt work (i was tired), it was only after trying very complex fixes that i realised that bar one was actually bar 2. and the button i was wanting to push didnt have anything in, otherwise i would of picked up on that faster.

again, sorry if it sounds stupid, but it happened to me.