The thing is, it does work with most of the people. We were the unlucky few. Thus can be caused by multiple things, other apps on your phone being one. In reality, no developer can account for the millions of other apps on peoples phones that might be causing a conflict. You just gotta troubleshoot the best ya can.
Side note, try deleting hearthstones app data. You should be downloading about 1gig next time you launch the app. After that, you should be prompted to log in. Delete the Data, not cache.