Hello Alexander,
Do I ring, which activates the intercom for 30 sec, I can open the door. > Do you mean by pressing the button in the app or by pressing the button on the intercom itself?
If you are not able to actuate the electric strike by app, it may take too long to enter the building again and the intercom activation has already expired in the meantime. In that case, can you please try to configure your opener with the help of a second person?
Did you verify, that doorbell recognition is working reliably? Every time the Opener recognizes a doorbell ring, it adds an entry to the activity log.
Best regards
Georg