How to investigate why Session() expired and let users know
<p>How to investigate what is causing Session expiry?
I would like to give some advise to end-users who have the following problem with our website:</p>

<pre><code>If Session("xxxx") Is Nothing Then say something.. WHY??
</code></pre>

<p>Can I add something to web.config  to make sessions last longer or should I read the IIS log files to see why this happens?</p>
