The following has evaluated to null or missing:
==> namespace  [in template "config-browser/page-header.ftl" at line 78, column 64]

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Tip: If the failing expression is known to legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??
----

----
FTL stack trace ("~" means nesting-related):
	- Failed at: #if namespace == ""  [in template "config-browser/page-header.ftl" at line 78, column 59]
	- Reached through: #include "page-header.ftl"  [in template "config-browser/tigris-macros.ftl" in macro "startPage" at line 24, column 9]
	- Reached through: @startPage pageTitle="An error occured"  [in template "config-browser/error.ftl" at line 22, column 1]
----

Java stack trace (for programmers):
----
freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...]
	at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:134)
	at freemarker.core.EvalUtil.compare(EvalUtil.java:198)
	at freemarker.core.EvalUtil.compare(EvalUtil.java:115)
	at freemarker.core.ComparisonExpression.evalToBoolean(ComparisonExpression.java:78)
	at freemarker.core.IfBlock.accept(IfBlock.java:49)
	at freemarker.core.Environment.visit(Environment.java:347)
	at freemarker.core.Environment.visit(Environment.java:353)
	at freemarker.core.Environment.visit(Environment.java:353)
	at freemarker.core.Environment.visit(Environment.java:353)
	at freemarker.core.Environment.include(Environment.java:2955)
	at freemarker.core.Include.accept(Include.java:171)
	at freemarker.core.Environment.visit(Environment.java:383)
	at freemarker.core.Environment.invokeMacroOrFunctionCommonPart(Environment.java:889)
	at freemarker.core.Environment.invokeMacro(Environment.java:825)
	at freemarker.core.UnifiedCall.accept(UnifiedCall.java:84)
	at freemarker.core.Environment.visit(Environment.java:347)
	at freemarker.core.Environment.visit(Environment.java:353)
	at freemarker.core.Environment.process(Environment.java:326)
	at freemarker.template.Template.process(Template.java:383)
	at org.apache.struts2.views.freemarker.FreemarkerResult.doExecute(FreemarkerResult.java:183)
	at org.apache.struts2.result.StrutsResultSupport.execute(StrutsResultSupport.java:206)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:377)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:284)
	at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:179)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:263)
	at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:49)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.doIntercept(ConversionErrorInterceptor.java:143)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:152)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:152)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:67)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:133)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:89)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:175)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:99)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:209)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:196)
	at com.opensymphony.xwork2.DefaultActionInvocation.executeConditional(DefaultActionInvocation.java:299)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253)
	at org.apache.struts2.factory.StrutsActionProxy.execute(StrutsActionProxy.java:48)
	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:630)
	at org.apache.struts2.dispatcher.ExecuteOperations.executeAction(ExecuteOperations.java:79)
	at org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:140)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:177)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360)
	at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:433)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:891)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1784)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.base/java.lang.Thread.run(Thread.java:840)