FastAPI is running as an ASGI application, but Passenger is trying to use it as a WSGI application. Please use one of the following options: 1. Access the API via the FastAPI-specific endpoints (e.g., /api/*) 2. Configure a proper ASGI server like Uvicorn or Hypercorn outside of Passenger For development, you can run the app with: uvicorn app.main:app --reload Current path: /