Outlook Calendar Pipeline, error with Calendar Event Trigger

I am new to Pipelines and testing how to get QB to interact with Calendar Events in Outlook. I've successfully built a pipeline where a new QB appointment creates a linked Calendar Event, and another pipeline where an update to the QB appointment will update the linked Calendar Event. I'm now trying to go the other direction, where a change in time on the Calendar Event will update the QB appointment.

I'm getting an error on the very first trigger. I've included screenshots of my very simple pipeline below, and a screenshot of the activity log. I'm not understanding what the obstacle is, so any help is appreciated. Thanks in advance.