Chat Plugin CORS Policy error

WHY still issues with the CORS policy, when using the Chat plugin?
Error:
Access to XMLHttpRequest at ‘https://web.facebook.com/plugins/customer_chat/facade/?app_id=&attribution=biz_inbox&channel=https%3A%2F%2Fstaticxx.facebook.com%2Fx%2Fconnect%2Fxd_arbiter%2F%3Fversion%3D46%23cb%3Dffb96df353b7d5a9b%26domain%3Dpalazzo.ee%26is_canvas%3Dfalse%26origin%3Dhttps%253A%252F%252Fpalazzo.ee%252Ff15197b5d66820cd0%26relation%3Dparent.parent¤t_url=https%3A%2F%2Fpalazzo.ee%2Fen%2Ffurniture-lightning-textiles%2F&is_loaded_by_facade=true&locale=en_GB&log_id=2b88b237-9d6c-4b9c-8a5c-f622a7eb4fc9&page_id=190355403438&request_time=1706095236622&sdk=joey&should_use_new_domain=false&suppress_http_code=1’ from origin ‘https://palazzo.ee’ has been blocked by CORS policy: No ‘Access-Control-Allow-Origin’ header is present on the requested resource.
Just to mention, we have tried all the tips from the Help Center. Our site has been whitelisted from the Chat plugin settings etc. Can you give me any help?