Cannot open Wiki

User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36
Exception: ExceptionWindowController: Throwable occurred, logging the full stacktrace: java.lang.NullPointerException
 at org.olat.modules.wiki.WikiManager.lambda$getOrLoadWiki$0(WikiManager.java:464)
 at org.infinispan.compat.FunctionMapper.apply(FunctionMapper.java:40)
 at org.infinispan.cache.impl.SimpleCacheImpl.lambda$computeIfAbsentInternal$10(SimpleCacheImpl.java:1268)
 at org.infinispan.container.DefaultDataContainer.lambda$compute$6(DefaultDataContainer.java:339)
 at com.github.benmanes.caffeine.cache.BoundedLocalCache.lambda$remap$16(BoundedLocalCache.java:2043)
 at java.util.concurrent.ConcurrentHashMap.compute(ConcurrentHashMap.java:1853)
 at com.github.benmanes.caffeine.cache.BoundedLocalCache.remap(BoundedLocalCache.java:2038)
 at com.github.benmanes.caffeine.cache.BoundedLocalCache.compute(BoundedLocalCache.java:1991)
 at com.github.benmanes.caffeine.cache.LocalCache.compute(LocalCache.java:101)
 at org.infinispan.container.DefaultDataContainer.compute(DefaultDataContainer.java:338)
 at org.infinispan.cache.impl.SimpleCacheImpl.computeIfAbsentInternal(SimpleCacheImpl.java:1265)
 at org.infinispan.cache.impl.SimpleCacheImpl.computeIfAbsent(SimpleCacheImpl.java:1248)
 at org.infinispan.cache.impl.AbstractDelegatingCache.computeIfAbsent(AbstractDelegatingCache.java:343)
 at org.infinispan.cache.impl.EncoderCache.computeIfAbsent(EncoderCache.java:651)
 at org.olat.core.util.cache.infinispan.InfinispanCacheWrapper.computeIfAbsent(InfinispanCacheWrapper.java:118)
 at org.olat.modules.wiki.WikiManager.getOrLoadWiki(WikiManager.java:419)
 at org.olat.modules.wiki.WikiMainController.getWiki(WikiMainController.java:1251)
 at org.olat.modules.wiki.WikiMainController.(WikiMainController.java:206)
 at org.olat.modules.wiki.WikiManager.createWikiMainController(WikiManager.java:144)
 at org.olat.course.nodes.wiki.WikiRunController.(WikiRunController.java:128)
 at org.olat.course.nodes.WikiCourseNode.createNodeRunConstructionResult(WikiCourseNode.java:132)
 at org.olat.course.run.navigation.NavigationHandler.doEvaluateJumpTo(NavigationHandler.java:461)
 at org.olat.course.run.navigation.NavigationHandler.evaluateJumpToTreeNode(NavigationHandler.java:286)
 at org.olat.course.run.RunMainController.doNodeClick(RunMainController.java:640)
 at org.olat.course.run.RunMainController.event(RunMainController.java:499)
 at org.olat.core.gui.control.DefaultController.dispatchEvent(DefaultController.java:206)
 at org.olat.core.gui.components.AbstractComponent$1.run(AbstractComponent.java:240)
 at org.olat.core.logging.activity.ThreadLocalUserActivityLoggerInstaller.runWithUserActivityLogger(ThreadLocalUserActivityLoggerInstaller.java:108)
 at org.olat.core.gui.components.AbstractComponent.fireEvent(AbstractComponent.java:238)
 at org.olat.core.gui.components.tree.MenuTree.handleClick(MenuTree.java:297)
 at org.olat.core.gui.components.tree.MenuTree.doDispatchRequest(MenuTree.java:196)
 at org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)
 at org.olat.core.gui.components.Window.doDispatchToComponent(Window.java:1202)
 at org.olat.core.gui.components.Window.dispatchRequest(Window.java:398)
 at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:282)
 at org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)
 at org.olat.dispatcher.AuthenticatedDispatcher.processValidDispatchURI(AuthenticatedDispatcher.java:263)
 at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:184)
 at org.olat.core.servlets.OpenOLATServlet.executeUserRequest(OpenOLATServlet.java:269)
 at org.olat.core.servlets.OpenOLATServlet.doPost(OpenOLATServlet.java:216)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
 at org.olat.core.servlets.OpenOLATServlet.service(OpenOLATServlet.java:160)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
 at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
 ...