Smart LED 1S(Color) stopped working in Alexa app

My account is 1734622651, and I use china mainland server in xiaomi home app. A few days ago suddenly the 1S bulbs became unresponsive in Alexa app. My other yeelights still work OK, only the 2 Smart LED 1S bulbs I have stopped working.

I can control them in the xiaomi home or yeelight apps, and I can see in alexa if they are on or off, but Alexa app cannot turn them off/on. Just says unresponsive. Very frustrating because the whole family uses alexa to control the lights, and now I am the only one who can turn them on, and have to do one by one with my phone :frowning:

Can you help me fix? It worked a few weeks ago just fine!