This is probably due to how your WordPress installation is dealing with API requests.

Make sure your WordPress REST API is enabled and running. Also, make sure its endpoint is /wp-json/, this is essential for the plugin to work. You can ask your hosting provider support to help you set this up if this is not already the case.

If only some features fail (file uploads, or Claude and ChatGPT connecting through MCP) while the chatbot itself works, a security layer at your host is probably blocking those specific requests. See When Your Host Blocks AI Engine.