I created a Journey Builder Interaction and turned it on to TEST mode.
The Event Source for the interaction is a sendable Data Extension which is updated (via the API) every time someone new signs up through our website.
Contacts who do not already exist in 'All Subscribers' fail to enter the Journey Builder Interaction, and this is the error thrown:
Failed - ExactTarget.InteractionStudio.Activities.AllowMultipleDecision.ContactKey: Error binding data bound member.
Question #1: Does a contact have to exist in All Subscribers to be accepted into an interaction?
Question #2: How can I add contacts to All Subscribers when they first flow through Journey Builder?