After the release of HCEA, Halo Waypoint asked for a mandatory update to the newer version. Unfortunately, almost all Greek xbl users can't download it because an error code always comes up ("There's a problem with Xbox LIVE Marketplace. Please try again later Status code: 800700e8") and its entry has even disappeared from the A-Z Marketplace search
I even tried re-downloading it with one of my friends US Live account but when I tried to launch it with my main profile it said "You must sign in with the account that has purchased the game"
It's quite frustrating, so If anyone knows how to make it work, please write here :)