Yeah, this is a somewhat arbitrarily-chosen timeout. It measures the amount of time between a Component’s iframe being mounted and the component sending its “hello I’m ready to receive data” message back to Streamlit.
We show this error message if that timeout is exceeded. The error message will disappear if the component eventually does finish loading. It sounds like the message never goes away for you, which may mean the component is throwing an error that’s preventing it from loading. If you look at the error console in your browser’s developer window, do you see any errors?