CloudFlare Host error / Error 520 Connection timed out
How to Fix Cloudflares Error 520: Web Server Is Returning an Unknown Error Solved 100 %
How to Fix Cloudflare Error 520? Web Server Is Returning an Unknown Error


Host Error

Typically this error comes up because of a firewall setting blocking Cloudflare. In some cases the firewall sees the same IP (Cloudflares) too much, and further connections are blocked. The fix is to whitelist Cloudflares IP at the host/firewall.


error cpanel


Always Online caching
Development Mode

TCP Idle Timeouts Are Shorter Than 300 SecondThe Transmission Control Protocol (TCP) could also be the cause of error 520.
TCP is a standard protocol that establishes and maintains a network connection. If the TCP is set to timeout in under 300 seconds, it could cause the 520 error to pop up.

You can change the TCP service timeout using a CLI command:
  set service Service-HTTP-1 -svrTimeout 500