are you using the latest daily build 1.5.5? We have fixed this issue in this release.
Before version 1.5.5, also faulty requests were stored in the offline queue, which is why you see the error message pop up even after restarting your app. To clear the existing request queue, please set the (yet undocumented) property clearOfflineSendingQueueAtStartup of the VPlayGameNetwork component to true once when you start your app again. For testing on your phone, please completely uninstall the app and then install it again and it should be working fine again.