Rasa Chat Widget not working

Hi I am using Rasa Chat widget in index.html, with versions:

  • Rasa Version : 2.8.15
  • Minimum Compatible Version: 2.8.9
  • Rasa SDK Version : 2.8.3
  • Rasa X Version : 1.0.0

When running a server via python to host website on, I open this link and it is blak. Got response 200, but no UI shows up. do you have any solutions thanks