No digital twin backends available. The gateway connects to the Digital Twin QPU on AWS Lambda; ensure it is reachable and DIGITAL_TWIN_QPU_URL / DIGITAL_TWIN_QPU_API_KEY are set for the API gateway (user-service).
Default: DIGITAL_TWIN_QPU_URL = AWS Lambda base URL (ap-south-1). Restart user-service after changing env vars. Use the app via nginx (e.g. http://localhost) so API requests reach the gateway.