A few things to check
- Check if allow static lighting is enabled in the prj settings
- check if a level is set to being a scenario level and that this level is loaded.
- Occasionally a light actor can get corrupted so try to place a new static light, build lighting without changes then save and package. See if that light worked.
- Check your static meshes have light maps and they are enabled with the correct id in the mesh settings, not the mesh build settings.
- Add reflection captures.
Building lighting isn’t a difficult thing. There must be something you’re doing in your level preventing light maps being saved.