Error 500, 502 and 504 explained
What each code means on this platform and what to check for each.
| Code | Means | Usual cause |
|---|---|---|
| 500 | The application failed | A PHP fatal error. Read the PHP error log. |
| 502 | The proxy got an invalid response | PHP crashed or ran out of memory mid-request. |
| 504 | The response took too long | A long import, a slow external API, or a query with no index. |
What to do
- Check the status page
If it is platform-wide, the incident is already published and being worked on.
- Read the PHP error log
Sites → Logs. For 502 and 504 also look at the slow query log.
- Note whether it is one page or all of them
One page points at code on that page. All pages points at the site or the platform.
- Try again in a private window
To rule out a cached error page.
Repeated 504 on one admin screen
Usually a plugin doing a long job in the request rather than in a background task. Raising the timeout hides it; batching the work fixes it.