Same here, stopped working Friday afternoon whilst I was using it. Thought it was just one of those thing but having just tried again on both boxes it's still not working. Not tried resetting either box though so that may fix it.
I am also having issues with the app on both my V6 boxes. Once loaded the app seems to freeze as you cannot navigate within it, however you can exit out without resetting the box so I am unsure big it is actually freezing.
We've attempted to use the application in our office and we've been able to listen to the stations and navigate around the application but have had trouble with using the 'Back' button on the remote whilst in the application on a radio station.
Does this issue happen after they've been on the app for an extended length of time?
It might be worth contacting Radio Online to see if they've been made aware of this issue and are in the process of fixing it.