I have a Roku express. I have set up 6 Roku devices (different models) thru the app and named them based on the room they are in. All of a sudden I am not able to access Roku on my TV screen, I pressed the home button on the remote and I get a black screen, that particular device has disappeared from the list on the app on my phone also. Two of the devices say: “New device found” and I’m able to control them, the other 3 say: “Not found in network” and like I said the one that has the black screen disappeared from the list. Please help. I used to be able to control them all with remote and through the app.