I have a solar system...
The central star has a point light attached to it.
However, objects don't cast shadows on each other...
Planets are < 20 units from the star, so it's not a light falloff issue.
The point light is the only light source in the scene.
There are occasions when it works - moon 3 of planet 5 correctly casts a shadow on its parent and siblings, whereas none of the others do.
Here's a video showing the issue more clearly: https://youtu.be/rmlWlXjygk0
Note that there are issues both casting and receiving shadows for all but the outermost moon.
Everything is set to both cast and receive shadows, objects are in the correct layers and not marked static...
I've tried changing from forward to deferred but that only prevented me seeing any shadows at all.
What am I missing? How can I get Unity to cast shadows correctly?