127.0.0.1 refers to the local computer, which in this case would be the Android device itself. That is not where the web server is running. Try using the actual IP address instead.
My guess is that Nobert is running a Xojo Web app locally using port 8080 and is available using the browser (http://127.0.0.1:8080) but when the above code is used the error message shows.
Thank you Tim, I re-read what Paul wrote and now I think he is saying that the android device is using that IP too, so OP needs to use the actual computer IP and not 127.0.0.1.