While we are the developer of Proloquo2Go and Pictello, the apps are exclusively sold by Apple through the i Tunes App Store.
Sometimes, a unstable Internet connection will result in a slow speed to download and update apps, and cannot use Search on App Store. Reconnect to Internet You can try to reconnect your device to Cellular by going to Settings Wi-Fi.
Some may have had trouble updating apps, while others are unable to view Passbook apps when connecting from the Passbook application.
One reader spotted a solution from Apple's support forums that shows how to get around the issue: Off. Try to [update the apps again or press the button from Passbook].
No matter what you do your App Store shows a blank white screen–and it’s very frustrating!
But for others, the App Store was working fine until, without warning or apparent cause, the App Store or i Tunes Store just goes blank. So before you unnecessarily perform a bunch of troubleshooting steps, check Double-tap your Home button, find the App Store, and swipe up towards the top of the screen to close the app. When you double-tap the Home button and swipe up, We recently found a new trick that you can apply right now to have the App Store display its pages and applications.