Worker is not part of the workspace referenced by the Workflow target
The Worker targeted by the Known Worker Routing feature is not a member of the Workspace referenced by the Workflow Target
Ensure the Worker is a member of the Workspace referenced by the Workflow that is configured to use Known Agent Routing. Find out more about the Known Worker Routing feature here: https://www.twilio.com/docs/taskrouter/workflow-configuration/known-agent-routing