Yilight ceiling led temperature doesn't change

Hi,

I have a Yi-light ceiling led light and lately the temperature change stop working.
I don’t know if the problem is in the controller or elsewhere but the fact is that the light stays warm whatever I do. I opened the lid of the led light to make sure I am right and as I suspected, the cold led lights are off and aren’t affected by neither the remote nor the mi home app.
does anyone had this kind of problem? is there anything I can do?

Regards