Using Power Automate to Trigger Copilot Agents

Question

I am trying to trigger a topic in Copilot Studio using a recurring flow in Power Automate, but I’m encountering issues. I followed the setup procedures for creating the trigger, specifically the 'Sends a prompt to the specified Copilot for processing' action, which added a body variable on its own. I set up a topic trigger in Copilot Studio to run on an 'Activity.Name is equal to the name of my trigger' event.

I am sending the event from Power Automate, and the logs indicate that it is being sent, but nothing is happening in Copilot Studio. What am I doing wrong?