3150310 - Failed to synchronize a document with BI Platform on Lumira Designer

When trying to synchronize a document with BI Platform on Lumira Designer client tool , error below appears :

!MESSAGE [ZEN LUMX] Failed to synchronize document "XXX"
!STACK 0
com.sap.ip.bi.zen.connectivity.ConnectivityException: com.sap.hilo.common.json.JSONException: A JSONObject text must begin with '{' at 1 [character 2 line 1]
 at com.sap.ip.bi.zen.backends.lumx.DocumentServer.uploadDocumentInternal(DocumentServer.java:1621)
 at com.sap.ip.bi.zen.backends.lumx.DocumentServer.synchronizeDocument(DocumentServer.java:1178)
 at com.sap.ip.bi.zen.backends.lumx.LumxSystem.synchronizeDocument(LumxSystem.java:355)
 at com.sap.ip.bi.zen.ui.internal.view.documents.SynchronizeDocumentsAction$1.run(SynchronizeDocumentsAction.java:60)
 at com.sap.ip.bi.zen.ui.internal.view.documents.DocumentActionHelper$1.execute(DocumentActionHelper.java:33)
 at org.eclipse.ui.actions.WorkspaceModifyOperation.lambda$0(WorkspaceModifyOperation.java:110)
 at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2295)
 at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2322)
 at org.eclipse.ui.actions.WorkspaceModifyOperation.run(WorkspaceModifyOperation.java:131)
 at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:122)
Caused by: com.sap.hilo.common.json.JSONException: A JSONObject text must begin with '{' at 1 [character 2 line 1]
 at com.sap.hilo.common.json.JSONTokener.syntaxError(JSONTokener.java:423)
 at com.sap.hilo.common.json.JSONObject.<init>(JSONObject.java:193)
 at com.sap.hilo.common.json.JSONObject.<init>(JSONObject.java:319)
 at com.sap.ip.bi.zen.backends.lumx.RestfulWsHelper.uploadLumxDocument(RestfulWsHelper.java:91)
 at com.sap.ip.bi.zen.backends.lumx.DocumentServer.uploadDocumentInternal(DocumentServer.java:1609)

• SAP BusinessObjects Business Intelligence Platform 4.x
• Lumira Server  2.x 
• Lumira Designer 2.x
• Load Balancer 

KBA , BI-LUM-SRV-DEP , Installation, Deployment , Problem