same here. i used my developer account to build the game then added another account that i was using on my iphone device to test internally. at first it worked, but after a few days all my builds expired for no reason. i tried uploading a new build, there was no error in the process, the build was uploaded to the app connect store successfully but the tester could not install it. what was shown to the tester was exactly what you are experiencing. i tried sending an email to apple support, posting in the forum and have not received any response yet.
Topic:
App Store Distribution & Marketing
SubTopic:
TestFlight
Tags: