The VRM file is missing the "VRM" extension, which is weird. Maybe the VRM file format was changed.
The project is inactive, so I would recommend moving to "XR Animator" instead, since it works better - https://github.com/ButzYung/SystemAnimatorOnline
Maybe I will strip down the project in the future and remove a lot of stuff like tracking/mocap and integrate it with "XR Animator" leaving only the rendering part.