When I enable debug mode, cache status is Undefined. Does the extension work?

When I enable debug mode, cache status is Undefined. Does the extension work?

If cache status is Undefined, it usually means that a third-party caching tool is used. The extension is unable to identify the caching tool and, therefore, whether the page is cached or not. For example, the FPC Warmer works this way with Varnish cache:



However, even if you get the Undefined status, it doesn't mean that the page is not warmed. You may check the cache status by opening the developer console and switching to the Network tab. Then open the very first record (the same as the page URL key) and check the x-magento-cache-debug header. If it tells HIT, it means that the page was successfully warmed: