Recurrent window "Connect to iTunes to Use Push Notifications" which prevents me from using the app

There are now 2 apps on my ipad where a window with "Connect to iTunes to Use Push Notifications" keeps popping up repeatedly despite pushing "ok", and doesn't let me use or exit the app since this window keeps popping up. I end up having to restart my iPad, and then this keeps recurring with the same 2 apps if I try to reopen them. Any ideas how to make this stop? Thanks!