Do you have a lightmass Importance Volume?
Check your lightmap resolutions, lightmap UVs, Lightmass Importance Volume, default lightmass settings (environment color), and scene Lightmass Density (Alt+0). Make sure your walls are static.
Do you have a lightmass Importance Volume?
Check your lightmap resolutions, lightmap UVs, Lightmass Importance Volume, default lightmass settings (environment color), and scene Lightmass Density (Alt+0). Make sure your walls are static.