I greyed out at first too. I think you can make the lossless change after a bit of time, but you could also try rebooting the Amp and clearing the Spotify app cache (or reinstalling it).
My WiiM Amp can play lossless, so I don't think there is anything wrong with the device.
That worked, restarted the Amp and cleared the Spotify app cache. I should have thought about restarting the amp first myself

Thank you very much
