Sam problem here. Might have somethng to do with softwarevupdTe on the device. It started to go awry after I updated the ios on my iPad 2
Had pro for a few weeks. Worked great until just now when i updated my iPad 2 to the latest (8.1.1) OS. All i get is that weird message that is utterly useless. "Hmmm... Invalid appid". Tried validating my mail now, but that did not help...