Enabling Session State downs the SharePoint site in 2013

Question

I want to store my session in session state service. I am following this site for setting up it.

But when I enable it, my site gives me 500 Internal Server Error. When I trace it I see below log:

<EventData>
  <Data Name="ContextId">{80000319-0000-5A00-B63F-84710C7967BB}</Data>
  <Data Name="ModuleName">IIS Web Core</Data>
  <Data Name="Notification">1</Data>
  <Data Name="HttpStatus">500</Data>
  <Data Name="HttpReason">Internal Server Error</Data>
  <Data Name="HttpSubStatus">19</Data>
  <Data Name="ErrorCode">2147942583</Data>
  <Data Name="ConfigExceptionInfo">\\?\C:\inetpub\wwwroot\wss\VirtualDirectories\demo.test80a73222a2-f9b6-4085-9f5b-509b8d04f213\web.config ( 680) :Cannot add duplicate collection entry of type &apos;add&apos; with unique key attribute &apos;name&apos; set to &apos;Session&apos;
</Data>

I have enabled session state as follow:

<pages enableSessionState="true" enableViewState="true" enableViewStateMac="true" validateRequest="false" clientIDMode="AutoID" pageParserFilterType="Microsoft.SharePoint.ApplicationRuntime.SPPageParserFilter, Microsoft.SharePoint, Version=15.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" asyncTimeout="7">

And commented below line:

<!--<remove name="Session" /> -->

I have enabled third party authentication using Identity server, which adds below code in file:

<add name="SessionAuthentication" type="Microsoft.SharePoint.IdentityModel.SPSessionAuthenticationModule, Microsoft.SharePoint.IdentityModel, Version=15.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" />

Nothing added except that. Can someone help me understand what is wrong?

Answer 1

It tells you in the message that you've added a duplicate key of 'Session'. Remove your 'Session' key that you've manually created. SharePoint adds one by default or when you've provisioned the Session State service (forget which).