Lovable deployment failed? Find the step that broke first

The preview is blank or will not load

This happens before an external hosting build, so start in the Lovable project preview. Reload it, note the exact message shown by the project, and check the browser console for the first runtime error. Keep the preview failure separate from a later Vercel build or custom-domain error.

If the preview becomes available but publishing still fails, continue with the relevant publish or build checks below.

Lovable Publish reports an error

1. Copy the exact message shown after Publish. A custom-domain error can be separate from publishing to the project’s generated address.
2. Confirm whether the Publish dialog says the website is live and test the generated .lovable.app address.
3. If that address works but a custom domain does not, check whether Lovable reports the domain as Live and follow its current DNS setup instructions before rebuilding.
4. If publishing itself does not complete, use the exact status and error shown by Lovable. Keep this separate from a Vercel build log, which applies only when you deploy the GitHub project there.

Do not post account credentials, secret environment values or private database URLs when asking for help.

If the .lovable.app address works but a custom domain does not, use the dedicated Lovable custom-domain DNS and SSL checker.

The Vercel build fails after GitHub sync

Open the failed deployment’s Build Logs and find the first specific error above a generic message such as “command exited with 1.” Vercel recommends checking those lines and running the project’s production build locally; the final line often only reports that an earlier step failed.

• Vercel builds an old version: confirm Lovable has synced the intended changes to GitHub, then confirm Vercel is deploying that repository, branch and latest commit.
• Vercel cannot identify a current Lovable project: check that the resolved @lovable.dev/vite-tanstack-config version meets Vercel’s documented minimum of 2.6.2 for automatic detection. The framework checker reads the version from package metadata pasted into your browser.
• A package, script or environment setting is missing: follow the exact file or variable named in the first error. Add secrets only in the provider’s environment settings, then redeploy.
• The error is not clear: paste a redacted log into the local deployment error checker. It recognizes common patterns and does not upload the log.

Automatic framework detection has a version requirement; a lower version alone does not prove the project is impossible to deploy. Follow the current framework setup and lockfile for the project you have.

Vercel says Ready, but the live app shows 404 or a blank screen

A successful build only confirms that the deployment completed. Open the production home page, then test the exact URL that fails. A missing nested route in an older client-side Vite app can require a fallback rewrite; a current TanStack Start app uses its framework’s server routing. Applying an SPA rewrite to a server-rendered app can break valid routes.

Use the Lovable-to-Vercel 404 and version guide to identify the project type before changing routing configuration.