Working with Magento CE v1.9.2.3 with Redis

Doing development for a website that makes use of a separate frontend and admin server in their production environment. I'm attempting to deploy TaxJar and a custom module that I've written to the production environment. They both happen to make use of the same Magento PHP resource in code:


They've been wanting to install TaxJar for a while and were aware of the error but couldn't make sense of it. Now I've created a module that makes use of the same getSingleton resource and they both trigger the same 500 error whenever it's used in the production environment. Here is the error message on TaxJar:

PHP Fatal error: Call to a member function isLoggedIn() on a non-object in /var/app/current/app/code/community/Taxjar/SalesTax/Model/Observer/AdminNotifications.php on line 31

Worth noting this 500 error does not occur in my local environment, development, or staging where the frontend and admin instances are not separated and do not make use of Redis.

Has anyone ever seen an issue similar to this for other modules or extensions? What could be a cause of this error?

Some context around the code that is causing the 500 error in my custom module:

$session = Mage::getSingleton('admin/session');
if (!$session->isLoggedIn() || !$session->getData(self::IS_PASSWORD_EXPIRED)) {

The context for TaxJar:

    if (Mage::getSingleton('admin/session')->isLoggedIn()) {

In both cases it's using a conditional.

  • I think you should ask Taxjar to check it. May 20, 2017 at 18:02
  • @Phoenix128_RiccardoT but it occurs for a personal module that I wrote as well. I've completely removed TaxJar, just deployed my extension and it does the same thing. Remove my extension and the error goes away. What could be the issue with Mage::getSingleton('admin/session');?
    – sparecycle
    May 20, 2017 at 18:04
  • If you could share the line content raising the error I could try to figure out. May 20, 2017 at 18:05
  • Shared for both modules @Phoenix128_RiccardoT.
    – sparecycle
    May 20, 2017 at 18:19
  • Mmm... weird. Are you sure you correctly flush cache and no module is trying to override admin/session ? May 20, 2017 at 18:21

2 Answers 2


The session issue could be related to how your servers were configured. It's best to discuss this with your hosting provider or sysadmin support provider. The fix could be, cache and sessions need to be connected to redis on admin server.


The error is indicating that the call to Mage::getSingleton is returning something other than an object. I would first check to see if the result of Mage::getSingleton('admin/session') returns an instance of Mage_Admin_Model_Session. My guess is that there is something like code compilation enabled that you aren't aware of it accounting for.

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