Can you attach a screenshot of your automation for this?
The error indicates you haven't started an interaction with a key. By default, to run an activity, it requires an interaction session to be active. You can change this default behavior in the interaction manager by changing the activity property of RequireInteraction to false.
Means that the activity that you are running requires an active interaction. This is configured in the Interaction.xml by the Activity attribute: RequiresInteraction in the <Activities> section. If an interaction is not required be sure to include RequiresInteraction="false" (case sensitive) as an attribute of the Activity. Else resolve this issue without doing that, start/activate an interaction.