Paying User Here: Tried Step-by-Step in Streams Endpoint Overview To No Avail

Followed everything in https://docs.d-id.com/reference/overview-1#-code-example (precisely) even until "Server started on port localhost:3000" shown in Terminal. Every time I use Safari or Firefox (I'm using macOS Monterey 12.6.6), the page loaded, but clicking on Connect button does not do anything (the Roman character does not appear). Do you think I missed a step? I'm developing an AI chatbot using your chat.D-ID app and was looking at code example to see how it works, but even the sample code doesn't work? Can you please help? Thank you.