it might be how ur setting up ur lights , you have to make sure ur lights are touching the walls , how far they radiate , u should be able to see it in wed, under preferences u can toggle it on or off , when u click on a light in any view port , u should see if a yellow circle arround it which shows where the light reaches , if a light isnt reaching anything , wall or floor or something , it wont show at all. I'm not exactly sure how accurate i am here , but i think i'm right , i had a problem like this some time ago and solved it this way , check ur lights and see if they are reaching the floor/walls ect.