How to fix a smart home scene that is not working correctly

This article is useful as an editorial parent page for scene-related problems across lights, plugs and ecosystems.

1. Verify every device in the scene is currently reachable.
2. Test devices one by one outside the scene.
3. Check whether the issue is tied to one ecosystem or app only.
4. Review room assignment and duplicate-device entries.
5. Rebuild the scene only after simpler state and sync checks fail.

Core editorial page for scene not working intent.