Lovable app not working after publishing? What to check

This guide is for people whose Lovable app looked fine in the editor and now misbehaves on its published address. The usual suspects are few: a blank page, sign-in that fails, data that does not save, a live site that differs from the preview, and a custom domain that does not connect. Below, each symptom comes with how to check it and which part of Lovable's own documentation backs the advice. At the end, you will see why a test after each fix matters.

For the full pre-launch routine, read How to test a Lovable app before launch. For other builders, see the series hub.

First, rule out the simplest cause: preview and live are not the same

Lovable's published app is a snapshot. Per its documentation, only the current version is deployed, and later edits stay out of the live site until you click Publish, then Publish changes. A dot on the Publish button signals unpublished updates.

Check first:

1. Open the published address in a private window.
2. Look at the Publish button in the editor: is there a dot?
3. If yes, publish the changes and test again.

Also, drafts and the published app use the same database, according to the Lovable database documentation, so a data change made while experimenting is visible live.

Symptom: blank page or white screen

Lovable's debugging guide says that when a published app shows a blank screen, the error often appears only outside the preview.

How to check:

1. Open the published address and open your browser's developer tools (the Console tab).
2. Reload and copy the first red error message.
3. Note which page is blank and what you did just before.
4. Paste the exact error, the URL and that description into Lovable's chat.

The guide suggests trying "Try to fix" once or twice, then switching to Plan mode and asking for the root cause before more code changes. If repeated fixes have tangled the code, it suggests restoring an earlier working version from version history, then telling Lovable what you did.

Symptom: sign-in fails

If sign-in works in the editor but fails on the published app or on a custom domain, Lovable's authentication documentation points to the redirect settings.

How to check:

1. In Auth settings, Advanced, confirm that the published address or custom domain appears in the Redirect URLs list.
2. Check the Site URL.
3. If your app uses your own backend project rather than Lovable Cloud, these are not updated for you: add the addresses in that project's authentication settings.
4. If you use your own social sign-in credentials, add the new domain's redirect address in that provider's console too, and select it in Lovable.

For Cloud-backed apps, the docs say Lovable updates these automatically: publishing sets the Site URL to your lovable.app address unless you set one, and connecting a custom domain adds it to the redirect list. If it still fails, test with a brand-new account to separate a settings problem from a problem with one account.

Symptom: data does not save, or the wrong people see it

Lovable's documentation does not list a single cause for data not saving, so check in order:

1. Reproduce it on the published address with a fresh account, then reload the page.
2. Open the browser's Network tab and look for failed requests (error status codes) when you press save.
3. In Cloud, Database, look at the table. The table view does not refresh live, so click Refresh before concluding nothing was written.
4. Review the row-level security policies (More, Cloud, Database, RLS policies). These rules decide which rows each user can read or change. The view is read-only: ask Lovable in the chat to change a rule.
5. Run the security scan: Lovable's Quick scan checks database access rules when you publish.

Two cautions from the docs: Lovable refuses schema changes that could break the published app (such as dropping or renaming columns) unless you allow them in your permissions, and the scanners cannot promise complete security.

Symptom: works in preview, fails live

Besides the unpublished-snapshot case above, compare what differs: the address (so redirects and allowed origins), the session (private window, no saved login), and data (live data instead of your test rows). Reproduce with a second browser and a second device. When you report the problem to Lovable's chat, always give the published URL and the exact error.

Symptom: custom domain does not work

Custom domains need a paid plan and a published project. Lovable's custom domain page lists these known causes:

Steps from the docs: check the status under Project, Settings, Domains and click Check status; confirm your records with a lookup tool, including the full verification record; remove conflicting old records; click Retry rather than re-adding the domain; try an incognito window. The page says connected-domain changes usually apply within a few hours but can take up to 72 hours, and that a browser security warning can appear until the certificate is ready.

Why test again after every fix

Each fix is a new change on a project where the AI edits several files at once. A fix for the sign-in redirect can break the sign-up page; a database rule fixed for one table can hide data on another. After each fix, publish, then run the same checks on the published address. Tools that remember the previous run make this faster, because they point out what changed.

Test your Lovable app with Avalyz

Avalyz tests the published address from the outside, in real browsers, and returns a GO, NO-GO or INCONCLUSIVE verdict with evidence.

• Free test without sign-up at the free test page, 3 a day, or start one with https://avalyz.com/essai?url=YOUR_APP_URL.
• Read-only by default: nothing is created or changed.
• Optional test account: sign-in is the sole form submitted, then signed-in pages are explored.
• Each report compares with the previous run of the same app, so a regression after a fix shows up. You can paste the report back into Lovable's chat.
• Monitoring can re-run it on a schedule. See pricing.

FAQ

Why is my Lovable app blank only after publishing?

Per Lovable's debugging guide, the error often appears only outside the preview. Read the browser console on the published address and paste the exact message into the chat.

Why does my sign-in loop or fail on my own domain?

Usually the domain is missing from the redirect URLs, or the Site URL is wrong.

How long does a custom domain take?

Lovable says changes usually apply within a few hours and can take up to 72 hours.

Should I revert instead of fixing again?

Lovable's guide says that after repeated failed fixes, restoring a working version is often faster.

Where do I go next?

Test a Bolt app, or the vibe-coded app guide.