So I have a few different problems, which could have the same origin. I watched a lot of lighting tutorials for many hours and I just can’t find a solution. Would be so happy if anyone could help. 
In all of my levels (with different lighting principles and sources) the scenes (rooms, one with windows) are very dark and no matter what I do, they don’t get brighter. If I place a Rect, Sky, HDRI or Point Light, the only thing they can do is bringing in indirectional lighting, but the real light itself doesn’t work. (So just Directional and Spot Lights are working)
All of my materials seem to have no BaseColor (except the ones under Directional Light or Spot Lights). In the “Lighting only” mode I have seen that they are 100% black, so there is no lighting at all on them – so I think that is the problem (but as I said above, I can’t find a solution).
My Settings:
I use Lumens and did all settings like William in this tutorial
I’ve got an PostProcessVolume in my levels.
In one of my levels the scene lighting is only Directional Light and Skylight (doesn’t work) and in another one I just work with Spotlights (because other lights don’t work at the moment).
I think this newspaper are showing my material problem perfectly.
And here you can see, no matter how intense the Rect Light is, it does nothing (here shown in “Lighting only” mode):
For example two of my levels with different lighting. All colors in the scene are white, that’s why there are no different shades. I just want them to be brighter and don’t have these really dark spots.
