Also, if you are creating a hybrid mobile app from one that is running in the sandox (and not from another environment such as acceptance or production), make sure that you have deployed your app to the sandbox in the Mendix cloud first before trying to open the mobile app. If you try to open the app before doing this, you will receive the Cannot initialize app error message.
This error is shown when the client failed to load. Most of the time this is caused by an incorrect or unreachable URL. Make sure that the Android device can reach the app (e.g. by trying to open it in the Android browser). If you chose to build the Phonegap Build package yourself, you can unzip the package and check the
index.html file for a line resembling
mxapp.initialize("https://myapp.mendixcloud.com"); It should point to the URL of your app.
Having the same problem, Tried building the package myself and also build from portal . Both are failing. App is working in Android browser.