I'm a bit of a novice here, but as I understand your problem is triggering the message to the Alexa node. I found, as others that the listen node doesn't seem to trigger so now use a series of actions, e.g. a virtual switch that triggers when I ask Alexa a certain question, a presence sensor that notes when I come into the kitchen, or, as I use a tracker, when this is in the salon area.
Maybe you've already tried this, but just a suggestion.
Some ideas here