Impossible to connect to Nuxeo API Playground: https://nuxeo.github.io/api-playground/

• Connect to Nuxeo API Playground: https://nuxeo.github.io/api-playground/
• Click on CONNECT button using the default settings:
  • URL: https://demo.nuxeo.com/nuxeo
  • User: Administrator
  • Password: Administrator

The page is not able to connect and shows this error message:

make sure you activated the CORS config on your Nuxeo server 
Please check the Nuxeo URL and try connecting again.