Existing Conversation did not have a Frontline worker participant.
Possible Causes
Issue with Frontline routing configuration that caused no worker assigned.
Conversation might not have been created by the Frontline service. This error indicates that the code is directly using Conversation API to the create the conversation, and Frontline cannot determine the format of the call.
Something went wrong when the Conversation was created by the Frontline worker or admin.
Possible Solutions
Check that your routing is set up properly in your Frontline Console page and delete this Conversation using the Conversation API.