No output when an event is triggered from the API (Elsa v3)

Hi,

When i try to trigger an event from api i can't get any output. For example i created a workflow with elsa-studio. It has 2 activity
( Event->WriteLine). I gave a body like above. After Output of event was always blank. When i debug, endpoint don't go Event.cs.
{
"workflowInstanceId": "3a9277a46af2c03",
"input": {"param":"test"},
"workflowExecutionMode": 0
}

How can i solve that?
Thank you in advance