Short answer: In Prefect 3.x, “Status: Not Ready” means the deployment’s target work pool does not currently have any compatible, active workers polling it (or the pool/queue it targets), so Prefect cannot run that deployment yet. Common causes - No worker is running for the deployment’s work pool - Worker is running but polling a different work pool or the wrong work queue - The work pool is paused or was deleted/renamed - Worker type/integration mismatch (e.g., a Docker or Kubernetes pool but the worker can’t launch those jobs because dependencies or permissions are missing) - Network/permission issues causing the worker to disconnect How to diagnose 1) Inspect the deployment to see its work pool (and queue, if set):

prefect deployment inspect "<flow-name>/<deployment-name>"

2) Inspect the work pool to check readiness and see connected workers:

prefect work-pool inspect "<your-work-pool>"

3) In the UI, open Work Pools → select your pool. Check: - Pool readiness indicator (Ready vs Not Ready) - Workers tab for any active workers and their “last seen” time - Queues and whether your deployment’s queue matches what your worker is polling How to fix - Start a worker for the pool (and queue if applicable):

prefect worker start --pool "<your-work-pool>"
# If your deployment targets a specific queue:
prefect worker start --pool "<your-work-pool>" --work-queue "<queue-name>"

- If using Docker or Kubernetes pools, ensure the worker has the needed extras and access:

uv run --with 'prefect[docker]' prefect worker start --pool "<docker-pool>"
uv run --with 'prefect[kubernetes]' prefect worker start --pool "<k8s-pool>"

- Make sure the worker is pointing to the same workspace/API as your deployment - If the pool is paused, unpause it in the UI (Work Pools page) Helpful docs - Work pools and workers overview: Work Pools (Prefect 3) - Deploying from a project (prefect.yaml): How to deploy with prefect.yaml - Background on the workers model: Blog: Work pools and workers If you share: - The deployment name - The work pool (and queue) it targets - Whether you have a worker running and its logs …I can pinpoint why it’s Not Ready and get you to green quickly.