I'm having trouble getting a plugin to work correctly and discovered this error in the debug.log occurring every time a page in the admin is loaded:

PHP Fatal error:  Call to a member function get() on null in
/xxx/wp-includes/cache.php on line 123

This error obviously doesn't directly relate to the plugin itself, but it has been suggested to me that it could be related.

As a core Wordpress file, I'm wondering how serious this error is.

I'm unsure what initiated this error or what exactly it means... The plugin I am having trouble with is Codisto WooCommerce Amazon & eBay Integration, but I honestly don't know if the error is causing the trouble or not. The error received whilst attempting a sync on the plugin side is:

/sync - Woo Sync Request FAILED
sync/","status":404,"responsetext":"<html><head><title>404 Not Found</title>
<style type=\"text/css\"></style></head><body><h1>Not Found</h1><p>The
requested URL /codisto-sync/settings?t=1521610698623 was not found on this
server.</p><p>Additionally, a 404 Not Found error was encountered while
trying to use an ErrorDocument to handle the request.</p><hr><address>
Apache Server at xxx Port 443</address></body>

Any thoughts?

1 Answer 1


That line 123 references the WordPress object cache, see https://github.com/WordPress/wordpress-develop/blob/7c38750b162c784d92f54d9a36044c0f5318fe24/src/wp-includes/cache.php#L123

Sounds like you have an external object cache (Memcached, Redis, etc.) that isn't set up properly or a plugin that wrongly modifies WordPress' internal object cache (which is basically a no-op). This could be configured by your host too.

Try disabling all plugins to see if this still happens.

Your Woo Sync error sounds completely different though. You should ask about that in a separate thread if needed.

  • Hey, thanks for your input, swissspidy. I've been unable to readdress this issue since posting initially, but have finally downloaded a copy of the site onto my localhost to test this issue. The funny thing is, no errors are occurring in the localhost environment, so I'm unable to replicate the issue I'm having on the live site. I'm not keen on making changes to the live site, but I guess I shall have to. Commented Apr 18, 2018 at 7:55

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