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err:unkey:application:deployment_not_ready
The deployment you’re promoting or rolling back to can’t take traffic yet. You get HTTP 412.
Example response

Likely causes

  • The deployment is still building. The message is The deployment is not ready.
  • The deployment failed to build or never passed its health checks. Same message.
  • The deployment is shutting down. The message is The deployment is shutting down and cannot serve traffic.

How to fix

  1. Read the deployment with deployments.getDeployment. If promote or rollback isn’t in its availableActions, the call will fail.
  2. If it’s still building, wait for status to reach ready.
  3. If it failed, fix the build and deploy again.
  4. If it’s shutting down, promote a different deployment.
Last modified on October 6, 2026