title: ASP.NET session expired
body: <p>I am seeing an exception logged in my error logs which is <code>Microsoft.Reporting.WebForms.AspNetSessionExpiredExceptionAsp.net</code>.</p>
  
  <p>But I am not being able to reproduce it. After doing google search I understood that it is because of session expiring.</p>
  
  <p>My question is, what would be some reasons for this error and is there any way I can reproduce it by manually clearing the session?</p>
  
  <p>Error log:</p>
  
  <blockquote>
    <p>15/12/2015
    09:08:11Microsoft.Reporting.WebForms.AspNetSessionExpiredException:
    ASP.NET session has expired or could not be found    at
    Microsoft.Reporting.WebForms.ViewerDataOperation..ctor()    at
    Microsoft.Reporting.WebForms.ReportDataOperation..ctor(Boolean
    requiresFullReportLoad)    at
    Microsoft.Reporting.WebForms.HttpHandler.GetHandler(String
    operationType)    at
    Microsoft.Reporting.WebForms.HttpHandler.ProcessRequest(HttpContext
    context)    at
    System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
    at System.Web.HttpApplication.ExecuteStep(IExecutionStep step,
    Boolean&amp; completedSynchronously)   at
    Microsoft.Reporting.WebForms.ViewerDataOperation..ctor()    at
    Microsoft.Reporting.WebForms.ReportDataOperation..ctor(Boolean
    requiresFullReportLoad)    at
    Microsoft.Reporting.WebForms.HttpHandler.GetHandler(String
    operationType)    at
    Microsoft.Reporting.WebForms.HttpHandler.ProcessRequest(HttpContext
    context)    at
    System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
    at System.Web.HttpApplication.ExecuteStep(IExecutionStep step,
    Boolean&amp; completedSynchronously)</p>
  </blockquote>