Tracker HTTP API inject an event/intent to conversation with session id


I am trying to implement an external Service, which can inject an intent/event/message to a current Bot-User conversation by session id using Tracker HTTP API. In Rasa log file I can see Server new injected intents or messages to a tracker. The Problem is Rasa does not display any of it to the frontend of a user.

Do you know how should I proceed? Is it even possible to change or influence the flow of a conversation or trigger Bot intents by another service ?

Thanks in advance.

Kind regards,