HTTP 200 OK vs 520 Web Server Returned an Unknown Error
HTTP 200 (OK) is a 2xx Success response, while 520 (Web Server Returned an Unknown Error) is a 5xx Server Error response. 200 indicates that the request succeeded. The meaning depends on the HTTP method: GET returns the resource, POST reports the action result, HEAD returns headers only. In contrast, 520 means that cloudflare-specific. The origin server returned an unexpected response that Cloudflare could not process.
Description
The request succeeded. The meaning depends on the HTTP method: GET returns the resource, POST reports the action result, HEAD returns headers only.
When You See It
The most common HTTP response — indicates the request was processed successfully.
How to Fix
No fix needed. The request succeeded as expected.
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
200 is a 2xx Success response, while 520 is a 5xx Server Error response.
HTTP 200: The request succeeded. The meaning depends on the HTTP method: GET returns the resource, POST reports the action result, HEAD returns headers only.
HTTP 520: Cloudflare-specific. The origin server returned an unexpected response that Cloudflare could not process.
You encounter 200 when the most common HTTP response — indicates the request was processed successfully.
You encounter 520 when when Cloudflare receives an empty, unknown, or malformed response from the origin.
When to Use Which
For 200 (OK): No fix needed. The request succeeded as expected. For 520 (Web Server Returned an Unknown Error): Check origin server logs. Ensure responses include proper headers. Verify SSL configuration.