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Errors / HTTP errors

503 Service Unavailable

The server is up but cannot handle the request right now: overloaded, or in maintenance.

Nobody can use the site, or the feature, until it clears.

Seeing it on someone else’s site?

  • It is temporary by definition; try again in a few minutes.
  • Big launches, sales and news spikes cause it; the site is not gone.

Why it happens, if it is your site

  • Maintenance mode switched on, or left on: WordPress's .maintenance file after an interrupted update is the classic.
  • No healthy server behind a load balancer, or every worker busy.
  • The host throttling the site for using too many resources.
  • A dependency (the database, an upstream API) failing, and the app reporting itself unavailable.

How to fix it

  1. Check for a maintenance switch or a leftover .maintenance file in the site's root.
  2. Look at the servers' health checks, CPU and memory at the time, and the host's resource limits.
  3. For planned downtime, send Retry-After so search engines come back later instead of dropping pages.

Whose problem it is

Usually the server that answers the request.

Does your site have it?

Free, no account. We open your page and four more in a clean Chrome and list every error like this one, with the page and the click that caused it. How the free page check works.

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Often seen with

  • 502 Bad GatewayThe server you reached works, but the application behind it did not answer properly.
  • 504 Gateway TimeoutThe server in front waited for the application behind it, and gave up.
  • 429 Too Many RequestsYou, or someone on your network, asked the site too often, and it is making you wait.