How to make GTAO works in VR mobile preview?

General rendering modes are too heavy for potato PCs. I like to use ES3.1 shading mode for VR.
But AO never works somehow. If enable GTAO in VR, then the skylight does not work for the left eye.
Can someone tell me how to make GTAO works in VR mobile preview mode?

I dont think gtao works at all on desktop, if you did manage to get it to work, please tell me how.

Turn on mobile GTAO. Build for windows64 including ES3.1 shading. Provide the “-FeatureLevelES31” parameter to the binary file.
It’s done.

What? Not any indea?