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Cloudflare Error 520 (2026)

Error 520 is a Cloudflare response that indicates the origin server returned an unexpected, empty, or invalid response. In most cases, the issue is on the server side, not the user's.

Common Causes of Error 520:

- Application failure or backend server crash
- Server overload (CPU, memory, or database)
- Oversized or malformed HTTP headers
- Firewall blocking or conflicts with Cloudflare
- DNS or SSL configuration issues
- Invalid responses from the origin server

️ How to Fix It Quickly:

- Refresh the page and clear your browser cache (if you're a user)
- Check server logs (Apache / Nginx / application)
- Make sure your firewall isn't blocking Cloudflare IPs
- Verify DNS records and origin server configuration
- Test the origin server directly (bypassing Cloudflare)
- Reduce the size of HTTP headers and cookies
- Check server load and available resources (CPU / RAM)

Read the full guide in our blog