Guru has been archived and should eventually return. It's currently unavailable due to technical restructuring after Curse's acquisition by Twitch. When they'll get it back up is unknown. In the meantime, you can access Guru using online cache services like Wayback Machine: https://web.archive.org/web/2016030604…-t10440240.html
Guild Wars Legacy in the WSC-Connect App on Google Play
Guild Wars Legacy in the WSC-Connect App on the App Store