> For the complete documentation index, see [llms.txt](https://clients.medianova.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://clients.medianova.com/products/performance-cdn/static-content-delivery/advanced-configuration/caching/error-status-code-cache-expiration.md).
# Error Status Code Cache Expiration
Configure how long selected HTTP error responses remain cached on Medianova CDN edge servers.
**Error Status Code Cache Expiration** allows you to define cache durations for specific HTTP error status codes. Caching error responses can reduce repeated requests to the origin server, particularly when the same error is returned frequently.
You can configure Error Status Code Cache Expiration through the [Medianova Control Panel](https://cloud.medianova.com) or the [API](https://clients.medianova.com/api-documentation/performance-cdn/caching#put-api-v1-cdn-organization_uuid-resource-resource_uuid-4).
{% hint style="warning" %}
Cached error responses may continue to be served after the underlying issue has been resolved. Use cache durations appropriate to the error condition, particularly for temporary server errors.
{% endhint %}
## Configuration Steps
{% stepper %}
{% step %}
### Open Error Status Code Cache Expiration
Open your CDN Resource in the Medianova Control Panel and select **Caching**.
Error Status Code Cache Expiration configuration.
{% endstep %}
{% step %}
### Add a Rule
Under **Error Status Code Cache Expiration**, select **Add rule**.
The **Add Error Status Code Cache Expiration** dialog opens.
{% endstep %}
{% step %}
### Configure Cache Time
Enter the desired **Cache Time** and select the corresponding time unit.
This value determines how long matching HTTP error responses remain cached at the CDN edge.
{% endstep %}
{% step %}
### Select Status Codes
Under **Status Codes**, select the HTTP error status codes to which the configured cache duration should apply.
You can select multiple supported status codes within the same rule.
{% endstep %}
{% step %}
### Add the Rule
Select **Add rule**.
The configured rule appears in the **Error Status Code Cache Expiration** table.
{% endstep %}
{% step %}
### Save the Configuration
Select **Save** in the pending changes bar.
Review the pending changes and confirm the update to apply the configuration to the CDN Resource.
{% endstep %}
{% endstepper %}
## Cache Behavior
### Caching Error Responses
When the origin returns an HTTP error status code covered by a configured rule, the CDN can cache the error response for the specified duration.
Subsequent requests for the same cacheable resource can receive the cached error response without requiring another request to the origin until the cache duration expires.
For example, if a **404 Not Found** response is configured with a cache duration of 5 minutes, the CDN can reuse that response during the configured period instead of repeatedly requesting the missing object from the origin.
### Cache Expiration
After the configured cache duration expires, the CDN can request the resource from the origin again.
If the origin continues to return the configured error status code, the response can be cached again according to the applicable rule.
If no rule is configured for a status code, this feature does not assign a cache duration to that response.
## Important Notes
* Caching **404 Not Found** responses can reduce repeated origin requests for missing resources.
* Use short cache durations for temporary errors, such as **500 Internal Server Error**, **502 Bad Gateway**, **503 Service Unavailable**, and **504 Gateway Timeout**.
* Removing or modifying a rule does not automatically purge previously cached error responses. Existing responses remain subject to their current cache expiration.
* Error Status Code Cache Expiration controls the caching of HTTP error responses. It is different from Stale Cache, which allows previously cached content to be served when configured origin error conditions occur.
---
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