I had the same problem; were you already using one of the HBO apps (like HBO Now)? You have to completely sign out of HBO - not just shut down the app - or Roku gets confused. Once you do that, restart Roku to clear its cache and install the HBOMax app. Start it and select something to watch; you should be prompted to either sign up through the Roku service or choose the provider you're already using. There's a LONG alphabetical list of providers; select yours and provide your username and password when prompted.
Hope this helps. |