Hello @taz71129!
Thank you for reaching out to the Community Forums! Let’s get the app working for you again!
With the myATT app, it will not use data when you use it so there are no worries there! Please do me a favor and go to our Troubleshoot and Resolve page, select your make and model, then select App for some troubleshooting steps.
Have you noticed any other apps behaving similarly while on WiFi? If you have noticed this, we may need to take a look at the WiFi network itself. If you can please go into the phone settings and remove the saved network from the phone. Then, please restart the phone, and reconnect to the WiFi network.
Hope this helps! Have a fabulous rest of your day!
Katherine, AT&T Community Specialist