HTTP ERROR 500 {msg=XSLT transformation error for xslt/main_ead.xsl,trace=java.io.IOException: XSLT transformation error for xslt/main_ead.xsl at com.infolytics.kopac.solr.XSLTResponseWriter.write(XSLTResponseWriter.java:219) at org.apache.solr.response.QueryResponseWriterUtil.writeQueryResponse(QueryResponseWriterUtil.java:65) at org.apache.solr.servlet.HttpSolrCall.writeResponse(HttpSolrCall.java:897) at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:583) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:437) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:367) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:201) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:552) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:600) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1624) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1440) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:505) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1594) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1355) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:191) at org.eclipse.jetty.server.handler.InetAccessHandler.handle(InetAccessHandler.java:177) at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:322) at org.eclipse.jetty.server.handler.gzip.GzipHandler.handle(GzipHandler.java:772) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) at org.eclipse.jetty.server.Server.handle(Server.java:516) at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:487) at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:732) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:479) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105) at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:338) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:315) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:173) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131) at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:409) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:883) at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1034) at java.base/java.lang.Thread.run(Unknown Source) Caused by: net.sf.saxon.trans.XPathException: A sequence of more than one item is not allowed as the second argument of concat() at net.sf.saxon.expr.Expression.typeError(Expression.java:1157) at net.sf.saxon.expr.SingletonAtomizer.evaluateItem(SingletonAtomizer.java:200) at net.sf.saxon.expr.SingletonAtomizer.evaluateItem(SingletonAtomizer.java:32) at net.sf.saxon.functions.Concat.evaluateItem(Concat.java:92) at net.sf.saxon.functions.Concat.evaluateAsString(Concat.java:81) at net.sf.saxon.expr.instruct.SimpleNodeConstructor.processLeavingTail(SimpleNodeConstructor.java:216) at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:657) at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:138) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:429) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:371) at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:657) at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:138) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:429) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:371) at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:657) at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:138) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:429) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:371) at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:657) at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:138) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:429) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:371) at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:657) at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:138) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:429) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:371) at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:657) at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:138) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:429) at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:371) at net.sf.saxon.expr.LetExpression.processLeavingTail(LetExpression.java:610) at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:657) at net.sf.saxon.expr.instruct.Template.expand(Template.java:258) at net.sf.saxon.expr.instruct.CallTemplate$CallTemplatePackage.processLeavingTail(CallTemplate.java:534) at net.sf.saxon.Controller.transformDocument(Controller.java:2090) at net.sf.saxon.Controller.transform(Controller.java:1911) at com.infolytics.kopac.solr.XSLTResponseWriter.write(XSLTResponseWriter.java:217) ... 44 more ,code=500}