Zehnder Q350 Lan C installation

The Zehnder Q350 and Lan C is installed at my house 1 years ago.
By the way one day, when I removed the Zehnder app of mobile phone and installed again, the connection between phone and Lan C is not done.

I read carefully the user’s manual and tried press the reset button and factory reset button as well. But failed.
Among the 4 led in Lan C and only the “activity led” is stayed “Off”. The other 3 LED is lighting well as same as described in user’s manual. This means that the wi-fi is live and the connection between Q350 and Lan C is also fine. Only the “activity led” is still off, which maybe make the connection not feasible.

So, could you please tell me when the activity LED is “On” ?
Is it “ON” when the connection with app is done?
Or is it have to be “ON” before connection?


As far as I can tell, this question has nothing to do with openHAB but with the initial setup and configuration. I’m not sure you will find much help on this forum.