Hi ,
I am also in the process of testing the standard Fiori app by creating a extension project. Have made the necessary configuration for creating a sandbox environment. But when i am testing the app locally using sandbox environment then getting a blank screen only. Checked the console for errors and i am getting error related to component-preload.js (Error 404).On running my app-config file i am getting 404 error(i.e resource not found).
Attaching the screenshot of error message.