I go to build and build lighting only, then instantly fails. I get this error: “MapCheck: Error: WorldSettings_1 Maps need lighting rebuilt”. I have assets set to static and have lumen turned off.
I had this problem too, it was that the swarm agent for building light didn’t work. But I could build with the GPU Lightmass plugin (you need to temporary enable Support Hardware Ray Tracing in project settings for this too)

(post deleted by author)
What does the log say?
So I checked the log first and they had this line:
LogStaticLightingSystem: Warning: No importance volume found, so the scene bounding box was used. You can optimize your scene’s quality and lighting build times by adding importance volumes.
So I added an importance lightmass volume for the level. It stopped displaying that line.
Then here is the log running with the lightmass volume over all the objects not including the :
ogEOSSDK: LogEOS: Updating Product SDK Config, Time: 1301.214600
LogEOSSDK: LogEOS: SDK Config Product Update Request Completed - No Change
LogEOSSDK: LogEOS: ScheduleNextSDKConfigDataUpdate - Time: 1301.880005, Update Interval: 325.459106
LogEOSSDK: LogEOS: Updating Product SDK Config, Time: 1647.325562
LogEOSSDK: LogEOS: SDK Config Product Update Request Completed - No Change
LogEOSSDK: LogEOS: ScheduleNextSDKConfigDataUpdate - Time: 1647.426147, Update Interval: 301.532257
LogStaticLightingSystem: Running Lightmass w/ ImmediateImport mode ENABLED
LogStaticLightingSystem: Running Lightmass w/ ImmediateProcess mode ENABLED
LogStaticLightingSystem: Running Lightmass w/ Sorting mode ENABLED
LogStaticLightingSystem: Running Lightmass w/ Mapping paddings ENABLED
LogStaticLightingSystem: Running Lightmass w/ Mapping debug paddings DISABLED
LogEditorBuildUtils: Build time 0:00
LogUObjectHash: Compacting FUObjectHashTables data took 0.18ms
LogStaticLightingSystem: Warning: Failed to build lighting!!! Lighting build failed.
DumpUnbuiltLightIteractions
Lights with unbuilt interactions: 1
Light Light Source
Primitives with unbuilt interactions: 66
…(goes through the assets in the scene)…
(ends with)
Cmd: MAP CHECK NOTIFYRESULTS
MapCheck: Error: WorldSettings_1 Maps need lighting rebuilt
