403
what this HTTP status codes error means
How it shows up
HTTP/1.1 403 Forbidden
What it means
The server understood the request but refuses to process it. Unlike 401, signing in again makes no difference, because the problem is permission for this resource or action.
The usual cause in an AI-built app
In Supabase apps the user is often signed in, but a row level security policy or a table grant does not allow the action. Supabase answers that case (Postgres code 42501) with 403 for signed-in requests.
Check this first
Open the failing request in the browser Network tab and read the response body, which usually names the service's own error code.