Hi, In our Mendix application we receive the error below dozens times per day. Do you know what could be causing the error? --- java.lang.IllegalArgumentException: Ids should not be null at com.mendix.basis.component.InternalCoreBase.retrieveId(InternalCoreBase.java:991) at com.mendix.basis.session.PersistentSession.<init>(PersistentSession.scala:30) at com.mendix.basis.session.PersistentSession.<init>(PersistentSession.scala:38) at com.mendix.basis.session.SessionFactory$.apply(SessionFactory.scala:55) at com.mendix.basis.session.SessionFactory$.createPersistentSession(SessionFactory.scala:76) at com.mendix.basis.session.SessionFactory.createPersistentSession(SessionFactory.scala) at com.mendix.basis.session.SessionManager.getSessionById(SessionManager.java:234) at com.mendix.webui.requesthandling.helpers.SessionHandling.$anonfun$getSessionFromRequestUnsafe$2(SessionHandling.scala:35) at scala.Option.flatMap(Option.scala:188) at com.mendix.webui.requesthandling.helpers.SessionHandling.getSessionFromRequestUnsafe(SessionHandling.scala:33) at com.mendix.webui.requesthandling.helpers.SessionHandling.getSessionFromRequestUnsafe$(SessionHandling.scala:31) at com.mendix.webui.actions.client.RegularClientAction.getSessionFromRequestUnsafe(RegularClientAction.scala:21) at com.mendix.webui.requesthandling.helpers.SessionHandling.$anonfun$getSessionFromRequest$2(SessionHandling.scala:27) at scala.Option.flatMap(Option.scala:188) at com.mendix.webui.requesthandling.helpers.SessionHandling.getSessionFromRequest(SessionHandling.scala:25) at com.mendix.webui.requesthandling.helpers.SessionHandling.getSessionFromRequest$(SessionHandling.scala:23) at com.mendix.webui.actions.client.RegularClientAction.getSessionFromRequest(RegularClientAction.scala:21) at com.mendix.webui.actions.client.RegularClientAction.execute(RegularClientAction.scala:30) at com.mendix.webui.requesthandling.ClientRequestHandler.handleAction(ClientRequestHandler.scala:124) at com.mendix.webui.requesthandling.ClientRequestHandler.processRequest(ClientRequestHandler.scala:101) at com.mendix.externalinterface.connector.RequestHandler.doProcessRequest(RequestHandler.java:40) at com.mendix.external.connector.MxRuntimeConnector$1.execute(MxRuntimeConnector.java:72) at com.mendix.external.connector.MxRuntimeConnector$1.execute(MxRuntimeConnector.java:69) at com.mendix.util.classloading.Runner.doRunUsingClassLoaderOf(Runner.java:32) at com.mendix.external.connector.MxRuntimeConnector.processRequest(MxRuntimeConnector.java:75) at com.mendix.basis.impl.MxRuntimeImpl.processRequest(MxRuntimeImpl.java:909) at com.mendix.m2ee.appcontainer.server.handler.RuntimeHandler.service(RuntimeHandler.java:42) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:867) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:542) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1588) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1345) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:480) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1557) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1247) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.Server.handle(Server.java:502) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:364) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:765) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:683) at java.lang.Thread.run(Unknown Source) Kind regards, Hans Ganzeboom