Help: fix common Lovable + Supabase errors
Plain-English guides for the errors we see most in Lovable apps on Supabase. Each one explains the cause, the safe fix and how to check it worked.
Fix "new row violates row-level security policy" in Lovable
Your Lovable app won't save and Supabase returns 42501 'new row violates row-level security policy'. Here are the causes and how to fix each one safely.
Read the guideCould not find the function in the schema cache (Lovable + Supabase): how to fix it
Getting 'Could not find the function in the schema cache' in your Lovable app? Check which database your live app uses, then fix the 4 common causes.
Read the guideLovable blank white screen after publish: how to fix it
Your Lovable app shows a blank white page once published. Find the real error in the console and fix the common causes, like missing Supabase keys.
Read the guideLovable Edge Function error (non-2xx / failed to send request): how to fix it
Your Lovable app shows 'Edge Function returned a non-2xx status code' or 'Failed to send a request to the Edge Function'. Here's how to find the real error and fix it.
Read the guideLovable login works in preview but not live: fix Supabase auth redirects
Sign-in works in the Lovable preview but loops or goes to localhost on your live site? Fix the Supabase Site URL, Redirect URLs and Google callback.
Read the guideSupabase 30 October change: new table says permission denied (42501)
From 30 October 2026, new Supabase tables get no API access by default. Here's why your new table says permission denied and the safe fix.
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