Originally Posted by Blackharon
It seems like there's an issue with Testflights beta feature that lets Devs add devices without making a new build.
From what we see here, to get that to work properly you have to install your beta games through Safari. It won't work if you go through the testflight app or your email.
Go to Testflightapp.com and install you're game from there. That seems to work.
Tried that. Contacted Testflight and they asked me to install some debugger thingy and send to the error reports to them.