How to Fix 521 Error with Cloudflare in cPanel

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What Cloudflare 521 Means

Origin down: Cloudflare could not connect to your origin server at all.

Common Causes

  • Server offline or restarted
  • Firewall blocking Cloudflare IPs
  • DNS pointing to wrong IP
  • SSL certificate expired

Troubleshooting Steps

Check Server Status

cPanel → Metrics → Service Status → Verify Apache/Nginx is running.

Whitelist Cloudflare IPs

CSF or host firewall → Allow all Cloudflare IP ranges.

Verify DNS Records

A record must point to correct server IP (not localhost or old IP).

Solutions Table

CauseSolution
Server downRestart services or contact host
Firewall blockWhitelist Cloudflare IPs
Wrong DNSUpdate A record
SSL expiredRenew certificate


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