If the app cannot find your device or the buttons have no effect, check the following.
- The phone and the device are on the same Wi-Fi network (watch out for « guest » networks and split 2.4 / 5 GHz bands).
- The device is turned on.
- If an authorization request (code, PIN or « Allow » prompt) appeared on the screen, you confirmed it. If you declined, reconnect from the app to make it appear again.
- Enter the device's IP address manually if the scan fails (choosing its type).
- On Roku, enable « Control by mobile apps » in Settings → System → Control by mobile apps.
- On Samsung / LG TVs, make sure network control is enabled (see the remote wake-up article).
- As a last resort, restart the device and your internet router.