Are you receiving error code 907 or 963? Both 907 and 963 errors seem to have similar steps to solve them.
http://valuestuffz.blogspot.com/2015/06/how-to-fix-error-963-android-google-play.html
http://www.fixerrs.com/2015/07/google-play-store-error-963.html
If that's not helpful, try deleting the application, restarting your device, and then reinstalling. Make sure when you reinstall that you're on a WiFi connection rather than 3g/4g.
_CHAMPION