Directional Light not penetrating glass window

[derek-jackson]

Hi, how do I get a directional light to penetrate my glass window? I've tried exporting the glass material from Blender with Blend Mode as both Alpha Clip and Alpha Blend, and I've set Shadow Mode to both Alpha Clip and None, yet still the light doesn't seem to penetrate through into the interior.

I don't want to remove the glass entirely as users would then fall through the opening to the exterior.

Is there something else I need to do? I'd expect to see it on the floor and tables of the upper floor in this example.