For example, if I look at the credit card payment page at http://192.168.0.8:3000/ (on my LAN), it loads the web page, but incompletely without the card entry boxes. Even http://127.0.0.1:3000/ (IP for localhost) fails. Only http://localhost:3000/ appears to work.
Thanks for bringing this to our attention. The team is looking into this. At this point since you have successfully tested using localhost we recommend that you next deploy to further test in sandbox.