PHP Session lost after redirect; comes back after refresh
<p>I have a login code that had been working fine for a couple years. No code was changed, and the server hosts claim that nothing was changed that would effect sessions.</p>

<p>Here's the basic run-down:</p>

<pre><code>1. User enters login info

2. Sent to process.php
   - Sets a $_SESSION['userid'] variable if validation was successful
   - Redirected back to previous page (using exit after header())

3. $_SESSION['userid'] is not set.

4. Refresh Page.

5. $_SESSION['userid'] is now set properly.
</code></pre>

<p>All pages have <code>session_start()</code>. I've also tried using <code>session_regenerate_id(true);</code> and <code>session_write_close();</code> Nothing Has changed.</p>

<p>Any ideas on server configuration or errors in my code would be welcome.</p>
