Same issue. I am logged in through my Xfinity account. If I select a live stream it does nothing. Worked on a Saturday then stopped on Monday. I have updat d the app, uninstalled and reinstalled, restarted Roku, restarted my router. Nothing. I contacted NESN and they replied to contact my point of purchase…this makes no sense. There is no point of purchase. Obviously an automated message.
Best option I can find is to run the app on my phone and then use Mirror for Roku to cast it to the tv.