This happens in two different cases.
I switch on the device, go to Sleep Timer, and it won’t turn on saying “Device closed”. I then try to go back, toggle the switch on/off (lights do turn on/off), but Sleep Timer won’t turn on.
I turn on the switch from the button on the main dashboard, but when I open the Yeelight (White) Bulb screen it shows as being off, although the light is on.
I don’t know if it’s slow to update the state, or what the problem is, but it’s often hit or miss 70% of the time.
Hello, Sleep timer only work while the device is on.
Yeelight app subscribes device state change listener, which means when state of device changes, the app would receive callback of the state change. As you described, it seems Yeelight app didn’t receive callback of the device state change(Power on state). So the app still take the device as off, “Device closed” showed when you turn on sleep timer.
This maybe caused by network issue, so when did the issue come out? With the latest version (2.3.12) ?
Just to be clear: it happens when I have already the lights turned on, so it shouldn’t be “device closed”.
I already had this issue before the latest update, hoping it would be fixed. As you say, I imagine the device is too slow, having to call the server after each command. I’ve seen others suggesting you to make it so there’s a local network of some kind. Indeed, once you’ve paired the device, I don’t see much reason why from your app you shouldn’t be able to perform simple commands without being on Wifi.