Hi @jthomas
Please which app are you using? Did you download this app from Google Play or another source? If you try on different phones, do you get the same issue? Are you able to connect to different servers such as the instances in play.dhis2.org?
This error might be too generic for the developers to figure out the issue. Please use the guide by @jaime.bosque to find out if there’s more info you could share to debug and understand the issue: Android Troubleshooting (technical guide)
Thanks!