Yeelight Lightstrip plus network timeout connection

[bigemme33]

Hi,
Suddenly the device disconnected from router.
I tried the following (based on the posts I read):

1. Resetting the device (at least 20 times)
2. Router frequency ONLY at 2.4ghz (no 5ghz)
3. router dns 8.8.8.8
4. No other changes to the router recently
5. Tried both yeelight app and mi home app.

Here is the error screen:

Any solution?
Thanks.