Fade doesn't fade just comes on full

I am setting up a schedule so my bedroom light comes on in the morning. I want it to start very dim and get to full brightness over 15 minutes. So I have added a schedule to turn on the light and set the fade slider to 15 minutes. But the light just comes on, to full brightness immediately.

I am using a Hue bridge and bulb.

What have I done wrong?

Thanks