Missing action (unpublish) for controller
Missing action (unpublish) for controller (Nextend\SmartSlider3\Application\Admin\Slides\ControllerSlides) in /wp-content/plugins/smart-slider-3/Nextend/Framework/Controller/AbstractController.php
At all of our customers where we saw this error message, the issue was caused by server cache. So if you see this error, we suggest getting in touch with your server host. Ask them to turn off " opcache" and any other server caches they are aware of, and that should solve the issue. Afterwards your server host could debug why the problem came up, if you would like to keep the server's cache.