Pressing 'Regenerate Thumbnails' button does not start the job

Installed the plugin on a WordPress 4.3.1 installation. When I press the ‘Regenerate Thumbnails’ button nothing happens…

I’m using a child theme of DualShock (by MyThemeShop and have tried the plugin while disabling all none (or lesser) essential plugins. But problem remains.

Any known issues with other plugins or any idea of a solution?

Thanks in advance

https://wordpress.org/plugins/regenerate-thumbnails-advanced/