Meross plugs not working

I‘ve added some Meross plugs via the Meross app to Homey. They appear with the right name but does not react - not manually, not in flows. Via the original Meross app the plugs work well. Any idea how to solve that? I reinstalled the app, and restarted Homey - no success.

Thanks for the help!

This is the place where you can ask for adding devices to the app.