This is a generic error you can see in the AI Engine admin when the server’s answer can’t be read. AI Engine expects a clean JSON answer; instead, it got something else: a PHP warning or a fatal error printed before the answer, or an HTML page from your host (a firewall “Access Denied”, a timeout page, etc.). Please look inside your PHP logs for any clues. Also, you can try to disable any other plugin that might interfere with the request (like cache and optimization plugins).

If you don’t understand what the error means in your PHP error logs, you can contact support and include your log file so we can help you sort it out.