I’m sorry for my confusion. I guess my question really is – what do you mean you “can access the file.”
When I browse to your xmlrpc URL, it returns “XML-RPC server accepts POST requests only” – which is what it should do regardless of if the plugin is enabled or not.
When I test your site with the XML-RPC tester at https://xmlrpc.eritreo.it/, it returns that it cannot access the XML-RPC service, which is what is expected when the plugin is enabled.
Am I misunderstanding what you mean by “accessing the file”?