I would like to add a form on the website that can be activated offline. I added two php files to the page (in attachments) - everything seems to work, but it returns wrong XML - on website https://auroradsp.com/activate. The case seems simple (we didn't change anything in the code except adding an API and a php connection) - what else needs to be done to make it work. We want to share this solution with people without logging in on our eshop or your limeLM website.
Everything works fine for us. We're using the latest PHP version and our HTTPS server is correctly serving the file with the correct mimetypes and headers.
You'll have to debug your setup (start by using the latest version of everything, and then work from there).