Cannot kick off swarm for unreal tournament

I have a 4.14 version of UE4 and a Unreal Tournament.Both are built from source.

UE4 works fine.But UT gives me an error said the swarm cannot kick off . The weird thing is UT actually can start the swarm agent, I can find it on the task bar.
I have tried rebuilding the lightmass,didn’t work.
This is the message I get from the console window

[2017.09.30-11.37.54:954][605]LightingResults: New page: Lighting Build - Oct 1, 2017, 3:37:54 AM
[2017.09.30-11.37.54:997][605]LogSwarmInterface: [OpenConnection] Registering TCP channel …
[2017.09.30-11.37.55:149][605]LogSwarmInterface: [OpenConnection] Connecting to agent …
[2017.09.30-11.37.55:161][605]LogSwarmInterface: [TryOpenConnection] Testing the Agent
[2017.09.30-11.37.55:674][605]LogSwarmInterface: [TryOpenConnection] Opening Connection to Agent
[2017.09.30-11.37.55:674][605]LogSwarmInterface: [TryOpenConnection] Local Process ID is 7864
[2017.09.30-11.37.58:405][605]LogStaticLightingSystem: Running Lightmass w/ ImmediateImport mode ENABLED
[2017.09.30-11.37.58:405][605]LogStaticLightingSystem: Running Lightmass w/ ImmediateProcess mode ENABLED
[2017.09.30-11.37.58:407][605]LogStaticLightingSystem: Running Lightmass w/ Sorting mode ENABLED
[2017.09.30-11.37.58:408][605]LogStaticLightingSystem: Running Lightmass w/ Mapping paddings ENABLED
[2017.09.30-11.37.58:409][605]LogStaticLightingSystem: Running Lightmass w/ Mapping debug paddings DISABLED
[2017.09.30-11.37.58:572][605]Cmd: MAP CHECK DONTDISPLAYDIALOG
[2017.09.30-11.37.58:572][605]MapCheck: New page: Untitled_1 - Oct 1, 2017, 3:37:58 AM
[2017.09.30-11.37.59:256][605]MapCheck: Info Map check complete: 0 Error(s), 0 Warning(s), took 683.641ms to complete.
[2017.09.30-11.37.59:279][605]LogEditorBuildUtils: Build time 0:05
[2017.09.30-11.37.59:734][607]Error, fatal in BeginJobSpecification
[2017.09.30-11.37.59:734][607]Error, fatal in EndJobSpecification
[2017.09.30-11.37.59:737][607]LogStaticLightingSystem:Warning: Failed to build lighting!!! Lighting build failed. Swarm failed to kick off.
[2017.09.30-11.38.00:405][607]DumpUnbuiltLightIteractions
[2017.09.30-11.38.00:405][607]Lights with unbuilt interactions: 0
[2017.09.30-11.38.00:406][607]
[2017.09.30-11.38.00:408][607]Primitives with unbuilt interactions: 0
[2017.09.30-11.38.00:489][608]Cmd: MAP CHECK NOTIFYRESULTS
[2017.09.30-11.38.00:489][608]MapCheck: New page: Untitled_1 - Oct 1, 2017, 3:38:00 AM
[2017.09.30-11.38.01:187][608]MapCheck: Info Map check complete: 0 Error(s), 0 Warning(s), took 697.86ms to complete.

Hi

This [video][1] might sort you out. Basically you have to build the lightmass in Visual Studio. Also highlighted in image below for convenience.

Make sure you exit all instances of the Swarm agent before doing all that.

Hope it helps

Hi
Thank you for replying and sorry for not replying you for so long.
I recompiled the Lightmass and restarted the computer,but it just can’t kick off …

After rebuilding, it works. Thanks.