There is a solution for the error code 208 in Steam VR:
1. Open Steam VR Settings and choose MANAGE ADD-ONS.
2. Turn on Pimax and Gamepad Support etc.
P.S: If the settings cannot be saved after restarting Steam VR, please save the settings and restart your computer before opening Steam VR. If the issue still persist, please try uninstall the Steam and Steam VR, and reinstall them.