I've built a game in Unity 2017.1.1f1 for the web. I have inputs to allow user to play with either the keyboard or a gamepad (in my case, a Gamecube USB). So far as I can tell, all controls work fine EXCEPT for my right (C) thumbstick. When I use the keyboard inputs which are an alternate for the C thumbstick, they work, and the C thumbstick works in the editor. These facts seem to rule out that there's any problem with my input settings or with my code or with my gamepad. Any ideas of what I can do to fix this? I'm not even sure where I would begin troubleshooting.
UPDATE: I built a UI to output a float for all axes. In the editor, I got a response for this thumbstick. On the web, the vertical axis for this thumbstick changed nothing.