Why won't my back or mute buttons click anymore?

After taking apart my controller to the individual shells, cleaning it, and reassembling, both my back and mute buttons won't click anymore.

After trying to figure out why I noticed the button for the mute inside to be further away from the external. It's the same on the back buttons. I know I put everything back the way it's supposed to go and everything aligned fine. All other buttons and sticks and triggers are fine as well.