You can log into the normal REDCap interface from your web browser on any mobile device -- you don't need to use the mobile app to go mobile!
The REDCap mobile app should only be used if you’re collecting data somewhere where there is no, or an unreliable, internet connection.
Mobile app users tend to run into more problems than users who access REDCap via a browser. For example, when you collect data in the mobile app, the data is only saved to your local device and not to our REDCap server, so it's much easier to lose data.
Please see the Project REDCap site for more caveats on using the app.