When you enable the CORS, you have to clear the cache by deleting the files located in
src/var/cache (path relative to the root of your application in its container).
For the "Sorry, but the API is unreachable... Please check your access to network." error, we need more
details on the error returned by the API, so could you please follow the steps in the following video
and provide us with the errors returned by the API?
Note: Sadly the video is in french only but maybe you can use the automatic translation function of
Youtube (+ the video itself) to understand what you have to retrieve, please come back to us if it's not the case.
The video: https://www.youtube.com/watch?v=-Ri4ocjBqc4