Static meshes aren't casting shadow on other static meshes

Hello Everyone.

I have few modular wall and floor pieces in my scene with Uv channel 1 for texturing and UV set 2 which was created by unreal for lightmaps. I am doing everything static.I have set the light map resolution of 512 in static meshes general settings and light map cordinate index to 1. i am using a static spot light with cast shadow on.

Attaching a screen shot.