No shadow on custom shader unless put a standard shader in scene

I build a scene with only my custom shaders, non of them cast or receive any shadows.

but if I put a cube with standard shader, all objects with my custom shaders cast and receive shadows correct (but only in the area around the cube with standard shader). I didn't make any change of the custom shaders or the settings.


I'm using two directional lights, unity pro,build for desktop,all graphic settings allow shadows,light cast shadows, and my custom shaders have cast and receive shadows functions.

please advice