FreeMarker template error:
The following has evaluated to null or missing:
==> pageNo  [in template "wap_article_list.ftl" at line 3, column 75]

Tip: If the failing expression is known to be legally null/missing, either specify a default value with 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 parenthessis: (myOptionVar.foo)!myDefault, (myOptionVar.foo)??

The failing instruction (FTL stack trace):
----------
==> ${pageNo}  [in template "wap_article_list.ftl" at line 3, column 73]
    #assign articlePage = articlePageByCa...  [in template "wap_article_list.ftl" at line 3, 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:98)
	at freemarker.core.EvalUtil.coerceModelToString(EvalUtil.java:382)
	at freemarker.core.Expression.evalAndCoerceToString(Expression.java:115)
	at freemarker.core.DollarVariable.accept(DollarVariable.java:76)
	at freemarker.core.Environment.visit(Environment.java:265)
	at freemarker.core.MixedContent.accept(MixedContent.java:93)
	at freemarker.core.Environment.visit(Environment.java:265)
	at freemarker.core.Environment.renderElementToString(Environment.java:1798)
	at freemarker.core.StringLiteral.evalAndCoerceToString(StringLiteral.java:116)
	at freemarker.core.ListLiteral.getValueList(ListLiteral.java:103)
	at freemarker.core.MethodCall._eval(MethodCall.java:94)
	at freemarker.core.Expression.eval(Expression.java:111)
	at freemarker.core.Assignment.accept(Assignment.java:106)
	at freemarker.core.Environment.visit(Environment.java:265)
	at freemarker.core.MixedContent.accept(MixedContent.java:93)
	at freemarker.core.Environment.visit(Environment.java:265)
	at freemarker.core.Environment.process(Environment.java:243)
	at freemarker.template.Template.process(Template.java:277)
	at com.paidot.ocms.utils.FreemarkerUtils.exportHtml(FreemarkerUtils.java:102)
	at com.paidot.ocms.utils.FreemarkerUtils.exportArticleHtml(FreemarkerUtils.java:239)
	at com.paidot.ocms.utils.FreemarkerUtils.exportArticleHtml(FreemarkerUtils.java:249)
	at com.paidot.ocms.utils.FreemarkerUtils.exportCategory(FreemarkerUtils.java:157)
	at com.paidot.ocms.controller.admin.StaticController$1.run(StaticController.java:184)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)