DEPLOYMENT_NOT_FOUND
what this Vercel error means
How it shows up
404 DEPLOYMENT_NOT_FOUND
What it means
The request went to a Vercel deployment that does not exist, because the deployment URL or ID is wrong or the deployment has been deleted.
The usual cause in an AI-built app
A common case is a URL saved while building, such as an OAuth or email redirect URL in Supabase or Firebase, that points to an old preview deployment that was later removed.
Check this first
Compare the exact host name in the address bar with the domains listed in your Vercel project settings.