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T4. Deploy failed

What this page helps you do​

Debug a deploy that did not complete or did not produce a healthy app.

Why it matters​

Failed deploys are normal. Random fixes make them worse.

You should already have​

  • a failed build or deploy log

Skip this page if​

  • the app is healthy and only the domain is broken

What to do​

  • read the logs from top to bottom
  • isolate whether the failure is build, startup, or runtime
  • check environment settings and runtime versions

Fix one root cause at a time.

Common mistakes​

  • changing code, config, and DNS all at once
  • skipping the logs
  • assuming the hosting provider is wrong before checking your own settings

Next step​

Go to T1. App works locally but not online.

Advanced notes​

TODO for contributors: add a “what kind of failure is this?” mini decision tree.