HTTP 424 Failed Dependency vs 521 Web Server Is Down
HTTP 424 (Failed Dependency) is a 4xx Client Error response, while 521 (Web Server Is Down) is a 5xx Server Error response. 424 indicates that the request failed because it depended on another request that failed (WebDAV). In contrast, 521 means that cloudflare-specific. The origin server refused the connection.
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 refused the connection.
When You See It
When Cloudflare can't establish a TCP connection to the origin server.
How to Fix
Check that the origin server is running and the firewall allows Cloudflare IPs.
Key Differences
424 is a 4xx Client Error response, while 521 is a 5xx Server Error response.
HTTP 424: The request failed because it depended on another request that failed (WebDAV).
HTTP 521: Cloudflare-specific. The origin server refused the connection.
You encounter 424 when in batch WebDAV operations when a prerequisite action fails.
You encounter 521 when when Cloudflare can't establish a TCP connection to the origin server.
When to Use Which
For 424 (Failed Dependency): Fix the failed dependency first, then retry the operation. For 521 (Web Server Is Down): Check that the origin server is running and the firewall allows Cloudflare IPs.