Is this occurring with one or multiple apps? Can you please provide me a screenshot of the error you receive?
Is this occurring with multiple apps? Are you trying to install the app using Wi-Fi or data?
Close all the apps, turn the device off and then turn it back on and perform these steps to the device:
1. From the home screen, swipe down the Status bar.
2. Tap the Settings icon.
3. Scroll to and tap System Updates.
4. Tap Update Profile.
5. Once the profile update is complete, tap OK.
6. The data profile is now up to date.
Is this occurring while you're connected to data or Wi-Fi? Are you able to browser the web?
I would like to know what are you trying to install or update? So we can look for more details about this error and help you out with this.
Mmm... I understand, have you tried to reset the device? If not working, try to repeat it in Wi-Fi and let me know the outcome.