← All status codes5xx – Server Error

HTTP 527 – Railgun Error

(Cloudflare) The connection between Cloudflare and the origin's Railgun server was interrupted (a now-legacy Cloudflare feature).

Other 5xx codes

500Internal Server Error501Not Implemented502Bad Gateway503Service Unavailable504Gateway Timeout505HTTP Version Not Supported507Insufficient Storage508Loop Detected511Network Authentication Required520Web Server Returned An Unknown Error521Web Server Is Down522Connection Timed Out523Origin Is Unreachable524A Timeout Occurred525SSL Handshake Failed526Invalid SSL Certificate530Origin DNS Error540Temporarily Disabled561Unauthorized598Network Read Timeout Error599Network Connect Timeout Error