In order to access a mobile app hosted in the cloud (even if it's the temporary free cloud instance), you would need to build it fully rather than use Make it Native. Make it Native is designed to only work for localhost, where both your device and the server are on the same network. Since running in the cloud is a separate network for the server, Make it Native won't work.
You should be able to do this using the Native Builder, however there are some extra pieces needed such as development certificates for ios/android and you'd need to follow the standard app signing/distribution process for either one.
If you only want to test your local dev app, I would suggest sticking to running locally only.