HTTP

HTTP 424 Failed Dependency vs 520 Web Server Returned an Unknown Error

HTTP 424 (Failed Dependency) is a 4xx Client Error response, while 520 (Web Server Returned an Unknown Error) is a 5xx Server Error response. 424 indicates that the request failed because it depended on another request that failed (WebDAV). In contrast, 520 means that cloudflare-specific. The origin server returned an unexpected response that Cloudflare could not process.

Description

The request failed because it depended on another request that failed (WebDAV).

When You See It

In batch WebDAV operations when a prerequisite action fails.

How to Fix

Fix the failed dependency first, then retry the operation.

Description

Cloudflare-specific. The origin server returned an unexpected response that Cloudflare could not process.

When You See It

When Cloudflare receives an empty, unknown, or malformed response from the origin.

How to Fix

Check origin server logs. Ensure responses include proper headers. Verify SSL configuration.

Key Differences

1.

424 is a 4xx Client Error response, while 520 is a 5xx Server Error response.

2.

HTTP 424: The request failed because it depended on another request that failed (WebDAV).

3.

HTTP 520: Cloudflare-specific. The origin server returned an unexpected response that Cloudflare could not process.

4.

You encounter 424 when in batch WebDAV operations when a prerequisite action fails.

5.

You encounter 520 when when Cloudflare receives an empty, unknown, or malformed response from the origin.

When to Use Which

For 424 (Failed Dependency): Fix the failed dependency first, then retry the operation. For 520 (Web Server Returned an Unknown Error): Check origin server logs. Ensure responses include proper headers. Verify SSL configuration.

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