I recently bought a 43" JVC smart set with Roku. The set works fine. I downloaded the Roku Mobile app to use my smartphone as a remote. That worked fine for a few days, then suddenly it wouldn't work and I got a popup error message (on the smartphone screen) asking me to either wait, close the app, or send feedback. Sending feedback I got a message that my phone wasn't connected to data (it was). Waiting did no good. The app SEES my tv (and also sees, and still controls, my old Roku2, but won't function with my JVC set anymore. I tried manual connection with the ip address, but it just shows the same set that way too (and still doesn't work with it).
Ironically, a third party Roku remote app does work with the set, (but it has annoying ad popups) I have to get passed download teasers and it doesn't have all the features, so I don't think the problem is with the set or the wifi connection. The app itself seems to be the problem. I tried it on two smartphones (Motorola and LG) and an RCA Tablet. The Roku Mobile app has the same problem on all of them (but the third party app works on all of them). I just wonder why it worked fine and then stopped working.
Similar. When I hit remote on my Roku app it takes me to devices. I click to connect and my television comes on but the app never acknowledges that it connected to the TV, so I am unable to use the app remote function.