Lovable preview not working
If the Lovable preview is blank, stuck, not found, or endlessly spinning, the cause may be temporary preview infrastructure, browser cache, broken runtime code, a GitHub sync issue, or a configuration problem inside the app.
Quick verdict
For preview issues, hard refresh first, test in another browser, check whether the app has a build or runtime error, then ask Lovable to inspect the preview failure without changing unrelated features.
Target topics covered
Start with simple checks
Preview problems are not always app-code problems. Try a hard refresh, use an incognito window, check another browser, and confirm your internet connection before asking for code changes.
Blank or white preview
A blank page often means the app loaded but crashed at runtime. Common causes include JavaScript errors, missing dependencies, route problems, broken auth redirects, configuration changes, or a component that fails during render.
- Open browser console and capture the first red error
- Check whether the issue started after a specific prompt
- Revert to the last working version if the crash is broad
- Ask Lovable to inspect runtime errors before redesigning the page
Not found or spinning sandbox
Lovable's own troubleshooting guidance notes that not found previews and spinning sandbox states can be temporary, connection-related, or connected to broken GitHub sync. If a hard refresh does not help, inspect the project sync and recent changes.
Preview fix prompt
The preview for [project/page] is [blank/not found/spinning]. It started after [change]. Please inspect preview logs, runtime errors, routing, config, and recent edits. Fix only the root cause and keep the current UI and data model unchanged.
Frequently asked questions
Why is my Lovable preview blank?
A blank preview often means a runtime error, broken component, missing dependency, auth redirect issue, or configuration problem is crashing the app after it loads.
Why is Lovable stuck spinning up the sandbox?
It can be temporary, connection-related, or tied to sync problems. Try a hard refresh first, then check recent changes and GitHub sync if it persists.
Should I rebuild the page when preview is blank?
Not immediately. First identify the runtime or configuration error, then fix the smallest cause.
Build faster with a better Lovable prompt
Turn the strategy from this guide into a structured Lovable prompt with pages, user roles, data, states, and acceptance criteria.