When a user chats with your chatbot, it uses your WordPress REST API to communicate with your server. If the API is not enabled or not reachable, it can result in issues like what you are experiencing. It seems that for your website, your REST API (/wp-json) requires users to be logged in.

This is not directly related to the AI Engine; it is related to your WordPress configuration. You can either change it yourself or ask your hosting service to help you with that.

If your REST API is open but the chatbot still fails on the live site only (uploads refused, replies that appear all at once or freeze), a security layer or a proxy at your host is probably getting in the way. See When Your Host Blocks AI Engine, which also gives you a message you can send to your host.