Lights Stopped Rendering

I’m making a map for TTT and yesterday something really weird occurred with the lights in the map.

All the exterior lights including the light_environment dont work. The entire map is dark. A few lights in some interiors work while the rest dont.

The only thing that changed since it broke was i started making an exterior building away from the main building.

Any idea what happened? The map compiles fine and no lin file is generated.

I asked on the fpsbanana forums too and someone there had this solution (which im sharing for anyone else who has the same problem):

must be the textures that are bugged.
your lights are working fine.

With the map open in Hammer hit alt+p, you may have invalid brushes, the problem checker may give you insight into your problem.

Your lights aren’t bouncing. I forget the reason why it happens.

looks like a leak so bad that it made light computation impossible,
maby a light source in the void or in a brush.
And you either turned off fullbright or it didn’t activate for some weird reason so it looks black.
Maby you check it by loading the .lin file of your map.

The only problems alt+p found were: Entity (func_breakable_surf) has unused keyvalue “error”

I fixed them, saved and closed the map and then ran alt+p again and those errors reappeared.

No pointfile file is generated when i compile the map.