I tried to figure out where he might be the problem, starting with the template change, disabling all plugins to look for conflicts, but none of it working.
Later I tried to do a test on xampp locally to see if it could be the server configuration where I have the site but the local copy of my website still does not work.
As a last attempt I tried to install the plugin on another site always on xampp but has an older version of joomla, 3.5.0 and the plugin is working properly.
I write this information hoping it will be useful.