iis - Invalid postback or callback argument when using loadbalancer and webgate -

hi have developed asp.net website deployed on 2 server. site working fine when access site using ip address of servers in url https://123.123.123.12/pagename.aspx. when access site using loadbalancer dns name (https://dnsname/pagename.aspx) , webgate of pages throwing following exceptions

"invalid postback or callback argument" or "the serialized data invalid."

this happending intermittently. same page, time shows correct data , throws exception.

when stopped website(iis) on 1 of server pages works excepted without throwing above exceptions.

i verified machine keys on both servers, machine key value same on both servers. there others websites on same servers working fine loadbalancer dns url (//dnsname/pagename.aspx) , webgate.

can me this?

below stacktrace

<description>an exception of type 'system.argumentexception' occurred , caught.</description>   <exceptiontype>system.argumentexception, mscorlib, version=4.0.0.0, culture=neutral, publickeytoken=b77a5c561934e089</exceptiontype>   <message>invalid postback or callback argument.  event validation enabled using &lt;pages enableeventvalidation="true"/&gt; in configuration or &lt;%@ page enableeventvalidation="true" %&gt; in page.  security purposes, feature verifies arguments postback or callback events originate server control rendered them.  if data valid , expected, use clientscriptmanager.registerforeventvalidation method in order register postback or callback data validation.</message>   <source>system.web</source>   <helplink />   <property name="paramname">&lt;undefined value&gt;</property>   <property name="data">system.collections.listdictionaryinternal</property>   <property name="targetsite">void validateevent(system.string, system.string)</property>   <property name="hresult">-2147024809</property>   <stacktrace>   @ system.web.ui.clientscriptmanager.validateevent(string uniqueid, string argument)    @ system.web.ui.webcontrols.hiddenfield.loadpostdata(string postdatakey, namevaluecollection postcollection)    @ system.web.ui.page.processpostdata(namevaluecollection postdata, boolean fbeforeload)    @ system.web.ui.page.processrequestmain(boolean includestagesbeforeasyncpoint, boolean includestagesafterasyncpoint)</stacktrace> 

after lot of research figured out both servers doesn't have windows updates(may missing patches). after performing windows updates on both machines site started working fine load balancer dns.