Please try the following:
- Restart the connected device.
- Force-closing and restarting the mobile app.
- Uninstall and reinstall the app.
- Check that your mobile device and your connected TV device are on the exact same network (i.e. one network can't be 5 GHz and the other 2 GHz).
- Confirm you are on the latest version of the app.
- If you have issues detecting your devices, try toggling your TV Wi-Fi between 5 GHz and non-5 GHz Wi-Fi networks.