Problems with my Yeelight 35W Nox Round Diamond

I have using my ceiling lamp Yeelight 35W Nox Round Diamond Smart LED Ceiling Light for months.

The last few days there are a lot of problems with the lamp. It goes off and on Randomly. Now it is not working at all anymore. Neither connects to the app nor turns it off from the remote.

Please advice

My MI ID: 1746401572

Turn off the router, connect to the server in mainland China with a mobile hotspot, and then try to upgrade the latest firmware.

The light is off. Cant make it on. Cant connect the app to the light, nighter withe the remote control.