Alexa Brightness control

Just bought a few Yeelight white led bulbs, i connected them to Alexa and i seem to able to turn the bulb off and on.
But when i try to change brightness ( most important feature) Alexa says that it can only do it when it is set at at " shade of white"
what does that mean? i can change brightness via Mi Home app, but i cant change it on alexa app ( but if i put via Mi home on 30% i will see 30% on alexa)

Please help
Thank you