A clear path forward
Why is my app's preview missing, blank, or not responding?
Ask Agent to check that the app's server is running and that the preview link points to it. A connected sandbox alone does not prove that the app has started.
The sandbox is the place where the app runs. The preview is the link to its running server, so a setup failure, stopped process or wrong port can leave that link blank.
- Confirm that the chat is using the intended repository and environment.
- Ask Agent to check the build and startup logs for the first error.
- Have it confirm that the server is listening on the expected port and the preview uses that port.
- If the app stopped, ask Agent to restart it and check the preview link again.
A missing Preview control is different from a link that opens but says nothing is listening. Record which you see. If the server is running but the preview still fails, keep the link, error and time of the check rather than repeatedly rebuilding without a diagnosis.
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Still stuck? Try troubleshooting with Agent.
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