I added a spotlight to a Unity scene and instead of just adding light, the surrounding environment got darker. What is happening here?

Some possibilities:

• You are using forward rendering and the maximum number of lights is exceeded when you add the spot light. This is what it looks like to me, like some light on the left doesn't get rendered when you add the spot. If so, switch to deferred rendering or split your scene into more objects.
• If you have some kind of automatic exposure, then adding a light might increase the luminance and cause other areas to get darker.

@Aressera Thanks a lot! I increased the max number of lights. Also gonna try switching to deferred

LorenzoGatti said:
I'm curious: when some lights are ignored, is there no way to get an explicit warning from the Unity engine? Trial and error doesn't seem a very efficient workflow, not all missing lights are as visible as the one in the OP's screenshots.

I don't know how Unity works internally, but in my engine the decision to cull lights is made for every mesh that is rendered, so a light might affect the objects closest to it, but would be culled for farther objects. So, if such a warning or logging was made by Unity, it would probably produce a huge number of culled lights in most scenes, since most lights would be culled for some object. So, such a warning would be not very useful.