Build lighting freeze unreal

Hello,

The building of the lighting of my little scene always freezes at a certain point.
I have a lightmass volume, in the swarm agent I set to true for use in standalone mode.

Here is my log :

23:03:14: Starting up SwarmAgent ...
23:03:14:  ... registering SwarmAgent with remoting service
23:03:14:  ... registering SwarmAgent network channels
23:03:14:  ... initializing SwarmAgent
23:03:14:  ......... certificate check has failed
23:03:14:  ...... initializing cache
23:03:14:  ......... using cache folder 'C:/Users/Sébastien/AppData/Local/UnrealEngine/4.25/Saved/Swarm\SwarmCache'
23:03:14:  ......... recreating SwarmAgent cache staging area
23:03:14:  ...... initializing connection to SwarmCoordinator
23:03:14:  ......... using SwarmCoordinator on RENDER-01
23:03:14:  ......... SwarmCoordinator successfully initialized
23:03:14:  ...... initializing local performance monitoring subsystem
23:03:16:  ... initialization successful, SwarmAgent now running
23:03:18: [Interface:TryOpenConnection] Local connection established
23:03:18: [Job] Accepted Job C50A6368-4DEBA5BB-FA9D95A5-03083991
23:04:23: [Job] Launched Job UnrealLightmass_2020-06-01_02-01-48_1126656-64bit.exe
23:04:23: [Job]     PID is 17940
23:04:23: [Job]     GUID is "C50A6368-4DEBA5BB-FA9D95A5-03083991"
23:04:24: LogLightmass: Display: Lightmass Win64 started on: MSI. Command-line: C50A63684DEBA5BBFA9D95A503083991
23:04:24: Failed to determine engine directory: Defaulting to ../../../Engine/
23:04:24: Failed to load 'aqProf.dll' (GetLastError=126)
23:04:24: File 'aqProf.dll' does not exist
23:04:24: Failed to load 'VtuneApi.dll' (GetLastError=126)
23:04:24: File 'VtuneApi.dll' does not exist
23:04:24: Failed to load 'VtuneApi32e.dll' (GetLastError=126)
23:04:24: File 'VtuneApi32e.dll' does not exist
23:04:24: Lightmass Win64 started on: MSI. Command-line: C50A63684DEBA5BBFA9D95A503083991
23:04:24: LogLightmass: Display: Processing scene GUID: C50A63684DEBA5BBFA9D95A503083991 with 6 threads
23:04:24: Processing scene GUID: C50A63684DEBA5BBFA9D95A503083991 with 6 threads
23:04:24: Building static lighting...
23:04:24: [OpenConnection] Registering TCP channel ...
23:04:24: [OpenConnection] Connecting to agent ...
23:04:24: [TryOpenConnection] Testing the Agent
23:04:24: [TryOpenConnection] Opening Connection to Agent
23:04:24: [TryOpenConnection] Local Process ID is 17940
23:04:24: [Job] Found a parent connection for PID 17940
23:04:24: [Job]     2D9697A4 -> 50D0FAFA
23:04:24: [Interface:TryOpenConnection] Local connection established
23:04:24: Skylight import processing 0.017s with CubemapSize 128
23:04:26: Measured CPU frequency: 2.59 GHz
23:04:26: FStaticLightingSystem started using GKDOPMaxTrisPerLeaf: 4
23:04:26: Number of texture mappings: 130
23:04:26: Number of fluid mappings:   0
23:04:26: Number of landscape mappings:   0
23:04:26: Number of BSP mappings:     0
23:04:26: Number of static mesh instance mappings: 130
23:04:26: Scene surface area calculated at 22035584.000 million units (10.967% of the estimated 200925888.000 million units)
23:04:26: Importance volume surface area calculated at 46.499 million units (18.480% of the estimated 251.622 million units)
23:04:26: Embree Build 0.1s
23:04:26: 
23:04:26: 
23:04:26: Collision Mesh Overview:
23:04:26: Num Triangles         : 335980
23:04:26: MeshInfos             :     0.0Mb
23:04:26: UVs                   :     4.9Mb
23:04:26: LightmapUVs           :     4.9Mb
23:04:26: Embree Used Memory    :    26.8Mb
23:04:26: 
23:04:26: 
23:04:26: Processing...
23:04:26: Couldn't gather the requested number of indirect photon paths! 171 gathered
23:04:26: EmitDirectPhotons complete, 0.067 million photons emitted in 0.0 seconds
23:04:26: Built photon segment map in 0.0 seconds
23:04:26: EmitIndirectPhotons complete, 0.028 million photons emitted in 0.0 seconds
23:04:26: Marking Irradiance Photons complete, 0.000 million photons marked in 0.0 seconds
23:04:27: Caching Irradiance Photons complete, 0.017 million cache samples in 0.9 seconds
23:04:27: Calculate Irradiance Photons complete, 0.000 million irradiance calculations in 0.0 seconds
23:04:28: Radiosity Setup 1.0s
23:04:30: Lighting 10.4%
23:04:30: Lighting 20.0%
23:04:30: Lighting 30.5%
23:04:31: Lighting 40.0%
23:04:31: Lighting 50.4%
23:04:32: Lighting 60.7%
23:04:33: Lighting 70.3%
23:04:33: Lighting 80.6%
23:04:34: Lighting 90.4%
23:04:34: Lighting 100.0%
23:04:34: [Job] Job is a success!
23:04:37: 
23:04:37: 
23:04:37: Total Static Lighting time:    8.46 seconds, 6 threads
23:04:37:  5.0%     0.4s    Scene setup
23:04:37:  0.3%     0.0s    Emit Direct Photons
23:04:37:  0.6%     0.0s    Cache Indirect Photon Paths
23:04:37:  0.4%     0.0s    Emit Indirect Photons
23:04:37:  0.2%     0.0s    Mark 0.000 million Irradiance Photons
23:04:37: 10.6%     0.9s    Cache 0.017 million Irradiance Photon Samples on surfaces
23:04:37:  0.0%     0.0s    Calculate 0.000 million Irradiance Photons
23:04:37: 94.8%     8.0s    Lighting
23:04:37:  0.0%     0.0s    Unaccounted
23:04:37: 
23:04:37: 
23:04:37: Total Irradiance Photon Caching thread seconds: 5.2
23:04:37:  0.0%     0.0s    Octree traversal
23:04:37:  0.0%     0.0s    0.000 million Visibility rays
23:04:37: 100.0%     5.2s    Unaccounted
23:04:37: 
23:04:37: Radiosity Setup thread seconds: 5.8, Radiosity Iteration thread seconds: 0.0
23:04:37: 
23:04:37: 
23:04:37: Total busy Lighting thread seconds: 31.00
23:04:37: 48.0%    14.9s    Texel and vertex setup
23:04:37: 10.3%     3.2s    Direct lighting
23:04:37:      0.0%     0.0s    Area shadows with 0.000 million rays
23:04:37:      2.8%     0.9s    Signed distance field source sparse sampling
23:04:37:      4.9%     1.5s    Signed distance field source refining sampling
23:04:37:      2.5%     0.8s    Signed distance field transition searching
23:04:37:      0.1%     0.0s    Unaccounted
23:04:37: 20.1%     6.2s    Block on indirect lighting cache tasks
23:04:37:  6.2%     1.9s    Block on IrradianceCache Interpolation tasks
23:04:37:  4.6%     1.4s    Volumetric Lightmap - 0.001 million samples
23:04:37:      3.5%     1.1s    VoxelizationTime
23:04:37:      0.1%     0.0s    GatherImportancePhotons
23:04:37:      0.0%     0.0s    DirectLightingTime
23:04:37:      1.2%     0.4s    FinalGatherTime
23:04:37:  4.1%     1.3s    Unaccounted
23:04:37: 
23:04:37: 
23:04:37: Indirect lighting cache task thread seconds: 6.21
23:04:37:  4.1%     0.3s    ImportancePhotonGatherTime
23:04:37:  0.0%     0.0s    CalculateImportanceSampleTime
23:04:37: 38.4%     2.4s    FirstBounceRayTraceTime for 1.261 million rays
23:04:37:  1.6%     0.1s    CalculateExitantRadiance
23:04:37: 
23:04:37: Traced 2.049 million first hit visibility rays for a total of 3.2 thread seconds (0.635 million per thread second)
23:04:37: Traced 0.011 million boolean visibility rays for a total of 0.0 thread seconds (0.333 million per thread second)
23:04:37: Scene radius 3998646.5, Importance bounds radius 4474.8
23:04:37: 130 Mappings, 0.521 million Texels, 0.108 million mapped texels
23:04:37: 
23:04:37: 85.3% of Total Lighting thread seconds on Texture Mappings, 0% on Volume Samples, 5% on Volumetric Lightmap, 0% on Visibility, 10.2% Unaccounted
23:04:37: 1 Lights total, 0.0 Shadow rays per light sample on average
23:04:37: Signed distance field shadows: 1.8 average upsample factor, 0.056 million sparse source rays, 0.267 million refining source rays, 0.019 million transition search scatters
23:04:37: 
23:04:37: 0.067 million first pass Photons Emitted (out of 0.022 million requested) to deposit 0.001 million Direct Photons and 232 Indirect Photon Paths, efficiency of 1.85%
23:04:37: 0.028 million second pass Photons Emitted (out of 0.028 million requested) to deposit 0.000 million Indirect Photons, efficiency of 1.31%
23:04:37: 0.018 million Photon Gathers, 0.000 million Irradiance Photon Gathers
23:04:37: 0.009 million Importance Photons found, 0.000 million Importance Photon PDF calculations
23:04:37: 28.1%    Bounce 1 Irradiance cache miss rate (0.056 million lookups, 0.016 million misses, 0.001 million inside geometry)
23:04:37: Final Gather: 1.0s on 0.297 million base samples, 4.2s on 0.965 million refining samples for 2 refinement levels. 
23:04:37:    77.3% due to brightness differences, 9.0% due to importance photons, 13.7% other reasons, Samples at depth: 47.1%, 52.9%, 
23:04:37: 238.0 Mb Peak Working Set
23:04:37: 
23:04:37: 
23:04:37: Lightmass on MSI: 13.2 sec total, 1.89 sec importing, 426 ms setup, 2.84 sec photons, 8.09 sec processing, 0 ms extra exporting [130/130 mappings]. Threads: 56.6 sec total, 26.2 sec processing.
23:04:37: Lighting complete [Startup = 1.89 sec, Lighting = 11.3 sec]
23:04:37: Failed to send back log file through Swarm!
23:04:37: [CloseConnection] Closing connection 50D0FAFA using handle 50D0FAFA
23:04:37: [CloseConnection] Connection confirmed for disconnection 50D0FAFA
23:04:37: [CloseConnection] Connection disconnected 50D0FAFA
23:04:37: [GetMessage] Safely returning to 50D0FAFA with no message
23:04:39: [MaintainConnections] Local connection has closed (50D0FAFA)
23:04:39: [MaintainConnections] Removed connection 50D0FAFA
23:05:38: [CloseConnection] Closing connection 2D9697A4 using handle 2D9697A4
23:05:38: [CloseConnection] Connection confirmed for disconnection 2D9697A4
23:05:38: [CloseConnection] Closing orphaned Job (C50A6368-4DEBA5BB-FA9D95A5-03083991)
23:05:40: [MaintainConnections] Connection 2D9697A4 is DISCONNECTING
23:05:43: [MaintainConnections] Connection 2D9697A4 is DISCONNECTING
23:05:43: [CloseConnection] Connection disconnected 2D9697A4
23:05:43: [GetMessage] Safely returning to 2D9697A4 with no message
23:05:46: [MaintainConnections] Local connection has closed (2D9697A4)
23:05:46: [MaintainConnections] Removed connection 2D9697A4
23:05:46: [MaintainConnections] All connections have closed

I don’t understand what is happening, i am using the preview quality in my tests.

Have you any idea?

well, I tried again and I waited hours and it works…
I just have to be patient, very patient…