Hue Iris bluetooth détected but no colors available

Good evening everyone,

I have installed Hue Essential on my wife phone for her to control a Hue Iris Bluetooth I offer her.

The lamp is detected properly but you can only switch it on/off and change the Kelvin and intensity, no possibility to change colour.

Would you have any idea on what I would have done wrong? Is there a hidden settings or is it a paid feature ?

Thanks in advance for any hint.