Yeelight LED Smart lamp D2


I have got a LED Smart lamp D2 bedside lamp half year ago.
From the beginning I faced an issue that the lamp can’t be turned on. When i push the physical button, it blinks for a while with blue light, then turns off. In the app I can see that the device is disconnected. I have installed the latest firmware a week ago but the problem still exists.
Can somebody give me some advice?

Thanks, br,