Here’s a checklist for emissive lighting:
- The object that is emitting light has to be static
- In the lightmass settings of the static mesh Use Emissive for Static Lighting has to be checked
- In the material Emissive (Dynamic Area Light) has to be checked
- In the material Used with Static Lighting has to be checked
- Additionaly, check the value of Light Map Resolution on the objects upon which you want to cast shadows