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HTTP error
503 Service Unavailable
The server cannot handle the request right now.
What it means
The server is temporarily unable to serve the request, usually because it is overloaded or down for maintenance. This code says the problem should pass, and the server can add a Retry-After header to say when to come back.
Common causes
- Planned maintenance
- A traffic spike or too many connections
- Rate limiting
- An attack that exhausts the server
- A dependency that is down, so the application takes itself out of service
How to fix it
If you are a visitor
- Wait a few minutes and try again
- Check whether the site has a status page
If you run the site
- Add capacity or caching if the server is overloaded
- Send Retry-After during maintenance
- Tell your users through a status page
- Pause monitoring alerts during planned work so they stay meaningful
Catch it before your users do
You can check the status code of any address right now. To hear about 503 errors as they happen, an HTTP(S) monitor requests the page around the clock, compares the response with the status codes you expect and alerts you when it does not match.
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