Why is Lovable not working?

Usually it's not Lovable itself but one specific failure — a build error, a stuck message, a Supabase hiccup, or a browser issue. Diagnose in order rather than guessing.

Why is my Lovable project stuck?

A stuck project usually means a message is still processing, a build failed silently, or you're in a fix loop. Check the chat status, the build/error banner, and version history before assuming it's frozen.

Why is Lovable chat stuck loading?

Chat usually gets stuck loading due to a network blip, a very large/complex request, or a backend timeout. Refresh first, then check the console before resending the same prompt.

Why is my Lovable preview blank?

A blank preview almost always means a JavaScript error is stopping the app from rendering. Open the browser console to find the exact error, then ask Lovable to fix it.

How do I fix a white screen in Lovable?

A white screen is a rendering crash — check the browser console for the error, paste it back to Lovable verbatim, and revert to a working version if repeated fixes don't clear it.

Why did Lovable break my website?

Something in a recent prompt likely had a side effect on shared code, styles or data. Check version history to see exactly what changed, then decide whether to revert or fix forward.

How do I undo Lovable changes?

Open Version history, find the last version before things went wrong, and revert to it — this restores the whole project to that exact state.

How do I fix a Lovable build error?

Read the exact error message and file it points to, paste it back to Lovable, and let it fix that specific error rather than describing the symptom vaguely.

Why does Lovable keep saying "try to fix"?

That prompt means Lovable's own fix attempt didn't fully resolve the error and it's suggesting another pass. If it repeats several times, stop and change approach rather than keep clicking it.

Why can't Lovable fix an error?

Usually because the prompt only describes the symptom, not the actual error text, or the root cause is outside the code Lovable can see (a third-party service, secret, or data issue).

How do I stop Lovable getting stuck in a fix loop?

Stop clicking automatic fixes, switch to Plan mode to find the actual root cause, and if that fails, revert to the last stable version instead of continuing to patch.

Why did fixing one thing break another?

Shared code — layouts, components, hooks, RLS policies — often affects more than the page you're focused on, so a targeted fix can have side effects elsewhere. Scope prompts narrowly and check related pages after each fix.

Why does my app work for me but not other users?

This is almost always a permissions or role issue — check Row-Level Security policies and the user_roles table rather than the front-end code, since it's usually about who's allowed to read/write data, not a bug.

Why am I getting a 403 error?

A 403 means the request was understood but denied — almost always a permissions or Row-Level Security issue rather than a bug in the request itself. Check who's making the request and what policy should allow it.

Why am I getting a 404 error?

A 404 means the thing being requested doesn't exist at that path — check for a broken route, a renamed page, a missing database row, or a wrong API endpoint.

Why am I getting "Failed to Fetch"?

"Failed to fetch" means the browser couldn't complete a network request at all — usually CORS, a down endpoint, a missing/invalid API key, or no internet connection, rather than a code logic error.

Why am I getting CORS errors?

CORS errors happen when your app's domain tries to call an API that hasn't explicitly allowed it. Fix it on the server side — either by adding your domain to the API's allow-list or by routing the call through a server function.

Why are environment variables missing?

Environment variables/secrets are usually missing because they were set for one environment (preview) but not another (production), never entered at all, or referenced with the wrong name in code. Ask Lovable to check what's configured rather than guessing.

Why has Supabase stopped connecting?

Usually an expired/rotated key, a paused free-tier project, an RLS policy change, or a genuine outage. Check the connection status and error message in Lovable before assuming your code broke.

Why is authentication suddenly broken?

Auth usually breaks after a schema change, an RLS policy edit, or an expired/misconfigured provider setting — check Logs first, then ask Lovable to diagnose before fixing.

Why did my database stop working?

A stopped database usually means a broken RLS policy, a failed migration, or (rarely) a paused/disconnected Supabase project — check Logs and ask Lovable to diagnose before changing anything.

Why is my custom domain offline?

Custom domains usually go offline because of a missing or changed DNS record, a certificate that hasn't issued yet, or the registrar's records pointing somewhere else — recheck the domain settings and your DNS provider.

Why won't my Lovable project publish?

Publishing usually fails because of a build error, an unresolved dependency, or a backend function that errors at build time — check the build log Lovable shows and fix that specific error first.

Why are Lovable builds failing?

Builds usually fail from a syntax/type error, a broken import, or a server function that errors during the build's checks — copy the exact error into your next prompt rather than asking Lovable to guess.

Why aren't my changes showing?

Usually a stale preview cache, an unsaved/unpublished change, or you're looking at the live site instead of Preview — hard-refresh, confirm the chat finished, and republish if needed.

How do I read Lovable console errors?

Open the browser console or Lovable's Logs panel, find the first error (later ones are often side effects), and paste the exact message and file/line into your next prompt.

How do I debug a Lovable project?

Reproduce the bug, gather the exact error from the console or Logs, ask Lovable to diagnose in Plan mode before changing code, then request the smallest possible fix.

How do I ask Lovable to diagnose an error without changing anything?

Use Plan mode, or explicitly tell Lovable in Chat to investigate and explain the cause without editing code — this stops it from making speculative changes while you're still working out what's wrong.

How do I get Lovable to make the smallest possible fix?

Describe the exact symptom and error, explicitly ask for the minimal targeted change, and tell Lovable not to refactor or touch unrelated files.

Why does my app work in preview but not when published?

Last checked 31 Aug 2026

Short answer

Preview and the published site can differ due to environment variables, caching, or build-time settings that only apply to one environment. Check environment/secret configuration and hard-refresh the published URL before assuming it's a Lovable bug.

Common causes

Environment variables/secrets set for preview but not carried through to production, or vice versa — see /questions/why-are-environment-variables-missing.
Caching — the browser or a CDN is serving an old version of the published site. Hard-refresh (Ctrl/Cmd+Shift+R) or test in incognito.
Different data — Preview might be using a different Supabase/Lovable Cloud project or dataset (e.g. test data) than what production points to.
Build-only errors — some issues only surface during the production build step (stricter bundling, minification) and don't appear in Preview's dev-like environment.
Domain/redirect differences — auth redirect URLs or CORS allow-lists configured for the preview domain but not the published (or custom) domain.

Diagnostic sequence

Confirm you're actually testing the latest published version — republish if you're unsure, then hard-refresh.
Open the browser console on the published site and compare any errors to what Preview shows (there should be none in Preview if it works there).
Check whether the feature depends on a secret/API key — ask Lovable to confirm it's configured for production.
If it involves login or an external API, check whether the published domain is included in the allowed redirect/origin list for that service.

What usually goes wrong

People assume "it's a Lovable bug" when it's actually a configuration difference between environments — most commonly a missing secret or an auth redirect URL that only lists the preview URL.

Fixing it

This works in Preview but fails when published. Console error on the published site: [paste]. Check whether any secrets, environment variables, or allowed URLs differ between preview and production.

For anything touching Stripe, OAuth, or email sending, double-check the production keys/URLs are genuinely production ones, not test/sandbox values left over from development.

Sources

Debug and improve your app

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