Volumetric lightmap all black

I’m trying to set up a static lighting scenario with stationary directional and skylight and some standard trees from the marketplace.
I can’t get any other result than this. All lightsamples are black and as soon as the trees leave the dynamic range of the cascaded shadowmap and enter into the static area they become all black.
This is true for different trees from different vendors.
Ladscape seems fine. But all the light sample points are black
What can be the cause?
Thanks

OK after some wild clicking on random buttons ( I have exhausted all my logical alternatives) the gorilla method fixed my problem. Apparently a skylight must be “movable”. Why? No idea. It’s just of the many quirks in UE that are not explained anywhere and that “just are the way they are”.
Anyway, my trees now look OK.