HTTP 520
Web Server Returned Unknown Error (Cloudflare)
Cloudflare
What does "HTTP 520 Web Server Returned Unknown Error (Cloudflare)" mean?
Plain-English Meaning
Cloudflare-specific. The origin server returned an empty or invalid response.
Common Causes
- Origin server crash mid-response
- Connection interrupted
- Large response timed out
What Users Can Do
Reload. Often transient. Wait a few minutes.
What Developers Can Do
Check origin server logs. Look for PHP fatal errors, memory exhaustion, or timeouts.
Related Status Codes
521
Web Server Is Down (Cloudflare) 522
Connection Timed Out (Cloudflare) 523
Origin Is Unreachable (Cloudflare) 524
A Timeout Occurred (Cloudflare)
Web Server Is Down (Cloudflare) 522
Connection Timed Out (Cloudflare) 523
Origin Is Unreachable (Cloudflare) 524
A Timeout Occurred (Cloudflare)
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