HTTP 500 Internal Server Error vs 520 Web Server Returned an Unknown Error
Both HTTP 500 (Internal Server Error) and 520 (Web Server Returned an Unknown Error) belong to the 5xx Server Error category. 500 indicates that the server encountered an unexpected condition that prevented it from fulfilling the request. A generic catch-all for server-side errors. Meanwhile, 520 means that cloudflare-specific. The origin server returned an unexpected response that Cloudflare could not process.
Description
The server encountered an unexpected condition that prevented it from fulfilling the request. A generic catch-all for server-side errors.
When You See It
When an unhandled exception occurs, a database connection fails, or server code has a bug.
How to Fix
Check server logs for the stack trace. Common causes: unhandled exceptions, database errors, misconfigurations.
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
HTTP 500: The server encountered an unexpected condition that prevented it from fulfilling the request. A generic catch-all for server-side errors.
HTTP 520: Cloudflare-specific. The origin server returned an unexpected response that Cloudflare could not process.
You encounter 500 when when an unhandled exception occurs, a database connection fails, or server code has a bug.
You encounter 520 when when Cloudflare receives an empty, unknown, or malformed response from the origin.
When to Use Which
For 500 (Internal Server Error): Check server logs for the stack trace. Common causes: unhandled exceptions, database errors, misconfigurations. For 520 (Web Server Returned an Unknown Error): Check origin server logs. Ensure responses include proper headers. Verify SSL configuration.