This error happens me always, what i do to reproduce this bug:
- Join a game
- Disconnect the gamepad before the game launches
- When you join, you must reconnect it.
Following those steps will reproduce the bug: You will not be able to walk.
This also happens when you start in the main menu (when you join Roblox on xbox, you must press A to continue). Disconnecting the controller there and reconnecting it will break the menu and you will not be able to navigate it.
This error was here in January 2019 and is still here.
I hope this gets solved!