Solr4 Problems with Alfresco Community 5.0.

[wuarmin]

I apparently have a problem with my production Alfresco 5 application. The log files contains tons of following errors:

catalina.out:

2020-12-09 16:28:23,622  ERROR [extensions.webscripts.AbstractRuntime] [http-bio-8443-exec-5] Exception from executeScript - redirecting to status template error: Server error (110912403).  Details can be found in the server logs.
 java.lang.RuntimeException: Server error (110912403).  Details can be found in the server logs.
	at org.alfresco.repo.web.scripts.RepositoryContainer.executeScript(RepositoryContainer.java:299)
	at org.springframework.extensions.webscripts.AbstractRuntime.executeScript(AbstractRuntime.java:378)
	at org.springframework.extensions.webscripts.AbstractRuntime.executeScript(AbstractRuntime.java:209)
	at org.springframework.extensions.webscripts.servlet.WebScriptServlet.service(WebScriptServlet.java:132)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.alfresco.web.app.servlet.GlobalLocalizationFilter.doFilter(GlobalLocalizationFilter.java:61)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:613)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)
org.alfresco.error.AlfrescoRuntimeException: 110910909 GetTextContentResponse return status is 500
	at org.alfresco.solr.client.SOLRAPIClient.getTextContent(SOLRAPIClient.java:1028)
	at org.alfresco.solr.SolrInformationServer.addContentPropertyToDocUsingAlfrescoRepository(SolrInformationServer.java:2451)
	at org.alfresco.solr.SolrInformationServer.addContentToDoc(SolrInformationServer.java:2438)
	at org.alfresco.solr.SolrInformationServer.updateContentToIndexAndCache(SolrInformationServer.java:2372)
	at org.alfresco.solr.tracker.ContentTracker$ContentIndexWorkerRunnable.doWork(ContentTracker.java:133)
	at org.alfresco.solr.tracker.AbstractWorkerRunnable.run(AbstractWorkerRunnable.java:40)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

alfresco.log

2020-12-09 16:28:23,622 ERROR [org.springframework.extensions.webscripts.AbstractRuntime] [http-bio-8443-exec-26] Exception from executeScript - redirecting to status template error: Server error (110912706).  Details can be found in the server logs.
java.lang.RuntimeException: Server error (110912706).  Details can be found in the server logs.
	at org.alfresco.repo.web.scripts.RepositoryContainer.executeScript(RepositoryContainer.java:299)
	at org.springframework.extensions.webscripts.AbstractRuntime.executeScript(AbstractRuntime.java:378)
	at org.springframework.extensions.webscripts.AbstractRuntime.executeScript(AbstractRuntime.java:209)
	at org.springframework.extensions.webscripts.servlet.WebScriptServlet.service(WebScriptServlet.java:132)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.alfresco.web.app.servlet.GlobalLocalizationFilter.doFilter(GlobalLocalizationFilter.java:61)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:613)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)

I think they belong together, but I could not find a reason until now.
The solr4 Dashboard looks good (i.e. enough memory available). 
If I navigate through, there are no errors visible, but sometimes the app becomes very very slow.
Maybe some of you can help me.

Thanks and best regards!