# What does a 500 error mean?

> A 500 error, or "Internal Server Error", is a generic HTTP status code returned by the server when it hits a problem that stops it from handling a request correctly.

- Source canonique : [https://allaux.fr/en/glossaire/erreur-500](https://allaux.fr/en/glossaire/erreur-500)
- Langue : EN
- Dernière mise à jour : 2026-09-30

## A symptom, not a diagnosis

The 500 code only indicates that something went wrong server-side, without saying what. The actual cause can vary widely: a fatal PHP error in the code, a database that's unreachable or overloaded, a corrupted configuration file, a memory limit exceeded, or a module or plugin left in a bad state after an update.

For a seller, a 500 error can make all or part of the site unusable, including the checkout, which directly halts sales. Finding the exact cause is therefore the priority, not just noting that the error occurred.

## Where to look for the cause

The precise cause shows up in the error logs: the application's log file (PrestaShop, WordPress) and the web server's error log (Apache or Nginx). Temporarily enabling debug mode also displays the error's technical detail directly on screen for the duration of the diagnosis.

The method then depends on the platform. For a shop, follow the diagnosis for the PrestaShop 500 error or for the WordPress critical error. For a method that works whatever the CMS, see where a 500 error comes from.

## The 500 error among the other 5xx codes

The 500 code belongs to the server error family, whose codes start with 5. It differs from its closest neighbours:

502 Bad Gateway: an intermediary in front of the site received an invalid response from the application server.

503 Service Unavailable: the service is unavailable, deliberately or temporarily, during maintenance for instance.

504 Gateway Timeout: the intermediary waited too long for a response and gave up.

Those three are covered in 502, 503 and 504 errors. A 500, by contrast, usually means the program did start, then stopped before producing a response.

## Don't confuse diagnosis with a fix

> Enabling debug mode or checking the logs helps identify the cause, but doesn't fix anything by itself. Debug mode should stay off outside of diagnostic sessions, so as not to expose technical details to visitors.

## FAQ

### How do you find out exactly what's causing a 500 error?

By checking the server's and application's error logs, or by temporarily enabling debug mode to display the error's technical detail.

### Can a 500 error hurt SEO?

Yes, if it persists or affects pages crawled regularly by search engines, it can lead to a drop in crawl frequency and, over time, partial deindexing.

### Does a 500 error always come from the site itself?

No, it can also come from the hosting (insufficient server resources, an unavailable database) or a poorly coded third-party extension, not just from the site's own code.