Raised exception while starting the application. Fix the error and restart.

Message
Failed parsing schedule at info from settings: null
Handler
org.fao.geonet.Geonetwork
Exception
java.lang.IllegalArgumentException: Failed parsing schedule at info from settings: null
Stack
java.lang.IllegalArgumentException: Failed parsing schedule at info from settings: null
	at org.fao.geonet.kernel.setting.SettingInfo.getLuceneIndexOptimizerSchedulerAt(SettingInfo.java:191)
	at org.fao.geonet.kernel.search.LuceneOptimizerManager.<init>(LuceneOptimizerManager.java:69)
	at org.fao.geonet.kernel.search.SearchManager.initNonStaticData(SearchManager.java:511)
	at org.fao.geonet.kernel.search.SearchManager.init(SearchManager.java:488)
	at org.fao.geonet.Geonetwork.start(Geonetwork.java:281)
	at jeeves.server.JeevesEngine.initAppHandler(JeevesEngine.java:448)
	at jeeves.server.JeevesEngine.init(JeevesEngine.java:191)
	at jeeves.server.sources.http.JeevesServlet.init(JeevesServlet.java:84)
	at javax.servlet.GenericServlet.init(GenericServlet.java:158)
	at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1144)
	at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1091)
	at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:983)
	at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4998)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5312)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:754)
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:730)
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734)
	at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1140)
	at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1875)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)