Vercel error

Updated 11 October 2026

Short answer

Vercel's error pages include a code in capitals, and Vercel's docs list what each means. The most common: FUNCTION_INVOCATION_FAILED (500), where your server-side code threw an error; FUNCTION_INVOCATION_TIMEOUT (504), where it ran longer than allowed; and DEPLOYMENT_NOT_FOUND (404), where the address doesn't point to a live deployment. For function errors, open your project's logs in Vercel at the time of the error to see the actual exception.

What's the problem

Your site or an API route on Vercel shows an error page with a code and an ID, or returns 500, 504 or 404.

Why it happens

  • Your function threw an error: a bug, a missing environment variable, or a failing database or API call (FUNCTION_INVOCATION_FAILED).
  • Your function took too long, often waiting on a slow database or outside API (FUNCTION_INVOCATION_TIMEOUT).
  • The address doesn't match a deployment, for example a deleted preview or a domain not assigned to the project (DEPLOYMENT_NOT_FOUND).
  • A Vercel incident, shown on Vercel's status page.

How to fix it

  1. Note the error code on the page and look it up in Vercel's error codes list.
  2. For function failures, open the project's logs in the Vercel dashboard and find the request at that time. The stack trace shows the cause.
  3. Check environment variables are set for the right environment (Production, Preview), and redeploy after changing them.
  4. For timeouts, find the slow call in your function and speed it up, cache it, or move it to a background job.
  5. For DEPLOYMENT_NOT_FOUND, check the domain is assigned to the right project and a production deployment exists.
  6. Check Vercel's status page for incidents.

What Preventionlabs checks

One click runs the full report on your domain. For this problem it shows whether your site loads, how fast, and where its redirects go; uptime checked every 5 minutes, with an email when the site goes down and when it is back; up to 50 pages from your sitemap, listing any that fail or are slow, plus broken links on them; your DNS: nameservers, addresses, DNSSEC, and records pointing at services that no longer exist; your domain's registration and expiry date. It has no connection to your host, so check the host's status page and logs as well.

Run your free report

Your first report is free, no card needed. Then A$50 a month, up to 10 domains. Read-only: it never changes anything.

Sources

  1. Vercel: Error Codesofficial docsWhen developing your application with Vercel, you may encounter a variety of errors.
  2. Vercel: Error Codesofficial docsFUNCTION_INVOCATION_FAILED Function 500 FUNCTION_INVOCATION_TIMEOUT Function 504
  3. Vercel: Error Codesofficial docsDEPLOYMENT_NOT_FOUND Deployment 404
  4. Vercel: Vercel Statusstatus pageGet email notifications whenever Vercel creates , updates or resolves an incident.

Related

Vercel deployment failed Open the build logs on the deployment's page: the first error line is the cause. Usually a build command failing, a missing environment variable, or bad config. Next.js error Find where it happens: at build time (read the build log), on the server (your host's function logs), or in the browser (the console). Each has its own fix. 500 Internal Server Error Your server hit an error it didn't handle. The cause is in the server's error log: usually a code bug, a bad config change, a failed plugin or a lost database. 504 Gateway Timeout Your app took too long to answer and the server in front of it gave up. Usually a slow database query, a slow outside API, or an overloaded server.

Preventionlabs is independent and not affiliated with Vercel. Product names are used only to describe the problem.

← All of Hosting