# Error metrics

Source: https://docs.fortrabbit.com/platform/metrics/errors
Published: 2026-10-24
Updated: 2026-10-24
Reviewed: 2026-10-24

> fortrabbit counts the 404, 500, 503 and 504 responses of an environment per hour or day. The usual causes and where to look next.


## Error counts

Each error metric counts the responses with that status code, for PHP and static files alike. A sample holds the responses since the sample before, a bar is the sum of its samples. In the box, the bare number is the count for the whole time frame, max and min are the busiest and the quietest hour or day.

Links below each chart open the access log filtered to that status code, for 500 and 504 also the PHP error log.

| Metric     | Status                | Usual cause                              | Read more                                         |
| ---------- | --------------------- | ---------------------------------------- | ------------------------------------------------- |
| 404 errors | Not found             | Missing file, broken link, crawler       | [404 errors](/dev/http-status-codes/404)  |
| 500 errors | Internal server error | Unhandled error in the code              | [500 errors](/dev/http-status-codes/500)  |
| 503 errors | Service unavailable   | All PHP processes busy, or PHP down      | [503 errors](/dev/http-status-codes/503)  |
| 504 errors | Gateway timeout       | PHP took longer than the time limit      | [504 errors](/dev/http-status-codes/504)  |

## Labels and lines

The values each metric shows in one bar, for the time frame, and on the summary page, and the lines drawn across the chart:



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- [HTTP status codes](/dev/http-status-codes)
- [Logs](/platform/settings/logs)
- [Metric values](/platform/metrics/values)