Yeelight cube disconnects, can't pair

I noticed cube was disconnected. It was just blinking blue/green light slowly. Tried to connect but nothing happens. Removed the device, still nothing. I press button for 5 seconds after I power on the cube, but it is blinking blue immediately when I power it on, and nothing changes when I hold button for 5 seconds. Scan fails (after scanning matter code). If I enter matter code manually in the app, it says bad code.

Any help?

First make sure the mobile app is up to date. After the device flashes blue, please wait for a few seconds without any operation, and wait until the lamp starts rainbow streamer to add the device.