Why does my Meshes turn Black when I Build Lighting?

When I build my Lighting, Most of the Meshes either turn black or darker then what their suppose to be. I don’t know if this is a Mesh or Material Problem. I have set the Light Map Resolution to 512 and the Light Map Coordinate Index to 1. Before doing that, the meshes would just turn darker. But after doing this, most of them turn black, but some are still just darker. The grey and black tiles are supposed to be a glossy white. How do I fix this?