You can also contact Elgato support directly. They helped me very quickly.

The reason for this is that the software is, in my opinion, completely immature. Sometimes it finds the lamps, sometimes not. I could not find a real pattern here. Other friends who have these lamps all (!) have the same problem. I don't understand why you can't simply add a lamp with a fixed IP in the software so that this search through the WLAN doesn't have to be repeated every time you restart.

must be due to your WLAN. do you have different hotspots? so that the lamp and the control device cannot land in the same WLAN after an IP change? It's just an assumption but it would be worth checking.

Have you tested on another device? That way you could find out if your device is the problem or not.