I bought a chromecast for $30 and now I can play HBO Go. I can not receive the menus on the tv screen, so I just pick and choose from my tablet, then miracast it to the TV. I do not have to subscribe to Chromecast just the $30 for the apparatus.
This is the only reason I am a member of this forum, trying to get answers about HBO. Trying to achieve this final outcome was beyond frustrating I know, as I subscribed to HBO GO through Hulu, which I receive quite nicely. We should let Hulu know to place a warning about the problems.
Good luck.