Had this exact issue for my steam VR project. Here’s the line:
the action manifest for (project name here) has an issue: " action paths must take the form ‘/actions//in|out/’. “actions/main/in/look up / down gamepad axis” does not. ".
To fix this I had to rename any input bindings I had made to remove any / (forward slash) characters. Replaced them with Underscores instead and now my controllers track again.